Answer:
two childrens are sitting on a see saw but can't swing.it means both weight is same (a=b)
Explanation:
hope it will help u please mark me brillientAnswer:
which subject is that question
Two children (each having a mass of 60 kg) are standing on the edge a merry-go-round (mass of 140 kg) as it spins with an angular velocity of 0.75 rad/s. The two children jump off the merry-go-round. What is the angular velocity of the merry-go-round after the children have jumped off
Answer:
The angular velocity after the children jump off is approximately 1.4 rad/s
Explanation:
The given parameters are;
The masses of each child, m₁, and m₂ = 60 kg
The mass of the merry-go-round, m₃ = 140 kg
The initial angular velocity, [tex]\omega_i[/tex] = 0.75 rad/s
The angular velocity after the children jump off = [tex]\omega_f[/tex]
According to the principle of conservation of angular momentum
The angular momentum = I × ω
The moment of inertia, I = m × R²
The total initial angular momentum = [tex]I_i \times \omega_i = m_i \times R^2 \times \omega_i[/tex]
The total angular momentum after the children jump off = [tex]I_f \times \omega_f = m_f \times R^2 \times \omega_f[/tex]
The initial mass, [tex]m_i[/tex] = m₁ + m₂ + m₃ = 60 kg + 60 kg + 140 kg = 260 kg
The final mass, [tex]m_f[/tex] = m₃ = 140 kg
According to the principle of conservation of linear momentum, we have;
[tex]I_i \times \omega_i[/tex] = [tex]I_f \times \omega_f[/tex]
Therefore;
260 kg × R² × 0.75 rad/s = 140 kg × R² × [tex]\omega_f[/tex]
∴ [tex]\omega _f[/tex] = (260 kg × R² × 0.75 rad/s)/(140 kg × R²) = 1.39285714 rad/s. ≈ 1.4 rad/s
The angular velocity after the children jump off, [tex]\omega _f[/tex] ≈ 1.4 rad/s.
The air pressure at the base of the mountain is 75.0cmof mercury while at the top is 60 cm of mercury given that the average density of air is 1.25kg/m³ and the density of mercury is13600kg/m³and g=10N/kg. calculate the height of the mountain?
Answer:
이 질문입니까?
Explanation:
평균 공기 밀도가 1.25kg/m³이고 수은 밀도가 13600kg/m³이고 g=10N/kg인 경우 산 기슭의 기압은 수은의 75.0cm이고 정상의 수은은 60cm입니다. 산의 높이를 계산?
The air pressure at the base of the mountain is 75.0 cm of mercury while at the top is 60 cm of mercury. The height of the mountain is approximately 0.1468 meters.
The pressure difference (∆P) between the base and the top of the mountain is given by:
∆P = ρgh
Where:
ρ is the density of the fluid (mercury) = 13,600 kg/m³
g is the acceleration due to gravity = 10 N/kg
h is the height of the fluid column (mountain)
We have the pressure difference: ∆P = 75.0 - 60.0 = 15.0 cmHg.
To convert cmHg to pascals (Pa), we use the conversion factor: 1 cmHg = 1333.22 Pa.
∆P = 15.0 × 1333.22
∆P = 19,998.3 Pa
h = ∆P ÷ (ρg)
h = 19,998.3 ÷ (13,600 × 10)
h = 0.1468 m
Therefore, the height of the mountain is approximately 0.1468 meters.
To know more about the air pressure:
https://brainly.com/question/15189000
#SPJ5
A boy shoves his stuffed toy zebra down a frictionless chute. It starts at a height of 1.45 m above the bottom of the chute with an initial speed of 1.23 m/s . The toy animal emerges horizontally from the bottom of the chute and continues sliding along a horizontal surface with a coefficient of kinetic friction of 0.231 . How far from the bottom of the chute does the toy zebra come to rest? Assume g=9.81 m/s2 .
Answer:
The answer is "4.97 m".
Explanation:
[tex]u = 1.23\ \frac{m}{s}\\\\[/tex]
[tex]H= 1.45 \ m\\\\[/tex]
[tex]\mu = 0.231\\\\[/tex]
The law of conservation tells us that heat energy at the top with kinetic energy at the top equals kinetic energy at the base.
[tex]mgh+\frac{1}{2}mu^2=\frac{1}{2}mv^2\\\\2gh +u^2 =v^2\\\\v=\sqrt{u^2+2gh}[/tex]
[tex]v=\sqrt{(1.23\ \frac{m}{s})^2+2(9.81 \frac{m}{s^2}) +(1.45\ m)[/tex]
[tex]=\sqrt{1.5129+19.62 +1.45}\\\\=\sqrt{22.5829}\\\\=4.75\ \frac{m}{s}[/tex]
Friction force is given by the formula
[tex]f=-\mu mg \\\\ma= -\mu mg\\\\a=-\mu g\\\\[/tex]
[tex]= -(0.231) \ (9.81\ \frac{m}{s^2})\\\\=-2.26611 \ \frac{m}{s^2}[/tex]
Now by using an equation of motion as
[tex]v^2-u^2= 2as[/tex]
From the above the distance traveled is
[tex]S=\frac{v^2-u^2}{2a}[/tex]
[tex]S=\frac{(0)^2-(4.75\ \frac{m}{s})^2}{2(-2.26611\ \frac{m}{s^2})}\\\\[/tex]
[tex]=\frac{-(4.75\ \frac{m}{s})^2}{2(-2.26611\ \frac{m}{s^2})}\\\\=\frac{-22.5625}{-4.53222}\\\\=4.97[/tex]
In other words, the distance from the bottom of the chute to the point where the toy zebra comes to rest is [tex]s = 4.97\ m[/tex]
pls someone help me pls…. and pls explain to me how
Answer:
1.12 × 10⁴ m/s
Explanation:
The escape velocity of the object v = √(2GM/R) where G = gravitational constant = 6.67 × 10⁻¹¹ Nm²/kg², M = mass of the Earth = 6 × 10²⁴ kg and R = radius of the Earth = 6.4 × 10⁶ m
Since v = √(2GM/R)
Substituting the values of the variables into the equation, we have
v = √(2GM/R)
v = √(2 × 6.67 × 10⁻¹¹ Nm²/kg² × 6 × 10²⁴ kg/6.4 × 10⁶ m)
v = √(13.34 × 10⁻¹¹ Nm²/kg² × 6 × 10²⁴ kg/6.4 × 10⁶ m)
v = √(80.04 × 10⁻¹¹ × 10²⁴Nm²/kg/6.4 × 10⁶ m)
v = √(80.04 × 10¹³Nm²/kg ÷ 6.4 × 10⁶ m)
v = √(80.04 ÷ 6.4 × 10¹³ ÷ 10⁶Nm/kg)
v = √(12.50625 × 10⁷ Nm/kg)
v = √(125.0625 × 10⁶ Nm/kg)
v = 11.18 × 10³ m/s
v = 1.118 × 10 × 10³ m/s
v = 1.118 × 10⁴ m/s
v ≅ 1.12 × 10⁴ m/s
when you go out to your car one cold winter morning you discover a 0.80 cm thick layer of ice on the windshield which has an area of 1.4m square if the temperature of the ice is - 2.0 degrees celsius and its density is 917 kg/m to the third find the heat required to melt all the ice
Answer:
The total heat required to melt the ice is approximately 3.473 MJ
Explanation:
The given parameters for the layer of ice are;
The thickness of the layer of ice, t = 0.80 cm = 0.008 m
The area of the wind shield, A = 1.4 m²
The initial temperature of the ice, T₁ = -2.0 °C = 271.15 K
The density of the ice, ρ = 917 kg/m
The temperature at which ice melts, T₂ = 0 °C = 273.15 K
We have;
The mass of the ice, m = ρ × t × A
∴ m = 917 kg/m³ × 0.008 m × 1.4 m² = 10.2704 kg
The specific heat capacity of ice, c = 2,090 J/(kg·K)
∴ The equation for the heat capacity of the ice to melt, is given as follows;
ΔQ = m·c·ΔT
Where;
ΔT = T₂ - T₁
∴ ΔT = T₂ - T₁ = 273.15 K - 271.15 K = 2 K
ΔQ = 10.2704 kg × 2,090 J/(kg·K) × 2 K = 42.930272 kJ
The latent heat to melt the ice, Q = The latent heat of fusion of ice, L × Mass of ice, m
The latent heat of fusion of ice, L = 334 kJ/kg
∴ Q = 334 kJ/kg × 10.2704 kg = 3,430.3136 kJ
The total heat required to melt the ice, H = ΔQ + Q
∴ H = 42.930272 kJ + 3,430.3136 kJ = 3,473.243872 kJ ≈ 3.473 MJ.
A red car has a head-on collision with an approaching blue car with the same magnitude of momentum. A green car driving with the same momentum as the other cars collides with an enormously massive wall. Which of the three cars will experience the greatest impulse
All three cars experience the same impulse.
Impulse is equal to change in momentum.
Each car starts with the same amount of momentum and ends up with zero, so the magnitudes of all three changes are equal.
Which solution has the greatest number of hydrogen ions?
blood, pH = 7.2
lemon juice, pH = 2
soda, pH = 3.5
bleach, pH = 13.5
Answer:
lemon
Explanation:
the lower the number the hier hydrogen ions
Answer: B
Explanation:
A motorcycle starts from rest and gains a velocity of 40m/s in 8 seconds. Find (i) acceleration and (ii) distance travelled by the motorcycle.
• Initial velocity (u) = 0 m/s
• Final velocity (v) = 40 m/s
• time (t) = 8s
Acceleration :[tex]\implies \sf a = \dfrac{\Delta v}{ t} \\ [/tex]
[tex]\implies \sf a = \dfrac{v - u}{ t} [/tex]
[tex]\implies \sf a = \dfrac{40 - 0}{ 8} [/tex]
[tex]\implies \sf a = \dfrac{40}{ 8} [/tex]
[tex]\implies \bf a = 5 \: {ms}^{ - 2} [/tex]
• Distance travelled by the motorcycle:[tex] \longrightarrow \sf {v}^{2} - {u}^{2} = 2as \\ [/tex]
[tex]\longrightarrow \sf {(40)}^{2} - {(0)}^{2} = 2 \times5 \times s \\ [/tex]
[tex] \longrightarrow \sf 1600 = 10s[/tex]
[tex]\longrightarrow \sf s = \dfrac{1600}{10} [/tex]
[tex]\longrightarrow \bf s = 160 \: m[/tex]
Describe an experiment to find the volume of an irregular- shaped ston
One way to measure the volume of any irregular object (in your case, a stone) is to submerge it completely under water and measure the change in the height of the water level. This change in the water level (let's say it goes from 50 mL to 65 mL) indicates that the stone has a volume of 15 mL .
4. An aluminium bar weighs 17 kg in air. How much force is required
to lift the bar while it is immersed in gasoline? The density
of aluminium is 170 kg/m' and that of gasoline is 42 kg/m
Explanation:
1ml = 2.7g
Xml = 1.5g
Divide 1.5 by 2.7 to find X.
Obviously, since 1.5 is less than 2.7, you know the answer will be less than 1.
(it’s .5555555555)
Sort the processes based on the type of energy transfer they involve. condensation freezing deposition sublimation evaporation melting thermal energy added thermal energy removed
Answer:
condensation - thermal energy removed
freezing -thermal energy removed
deposition - thermal energy removed
sublimation - thermal energy added
evaporation - thermal energy added
melting - thermal energy added
Explanation:
Thermal energy is heat energy. Processes in which heat is added involve the addition of thermal energy while processes in which heat energy is removed involves removal of thermal energy.
Condensation involves a change from gas to liquid, freezing involves a change from liquid to solid while deposition involves the settling of mobile particles at a place. All these processes involve a decrease in energy of particles.
On the other hand, sublimation is a direct change from solid to gas, melting involves a change from solid to liquid while evaporation involves a change from liquid to gas. All these processes occur when energy is added to the particles in a system.
Answer:
condensation - thermal energy removed
freezing -thermal energy removed
deposition - thermal energy removed
sublimation - thermal energy added
evaporation - thermal energy added
melting - thermal energy added
A person has power of 550 watt. What does it mean?
Answer:
It means that person can do work or can posses energy at a rate of 550 watts.
Or : can posses energy of 550 joules in one second.
Explanation:
[tex]{ \bf{power = \frac{work}{time} }}[/tex]
If you could travel 900 meters in 55 seconds, what is your speed?
(Answer in details=brainliest)
Answer:
The rate of change of distance is called speed it can also be defined as distance travelled per unit time,from these definition you can tell that the formula will be
speed=distance/time
in this question the distance is 900meters and the time is 55seconds therefore the speed will be:
s=900meters/55seconds
=16.36m/s
I hope this helps
You are pushing a cart at the grocery store. The cart is speeding up. a) When your friend drops a 50 pound bag of dog food into the cart you are pushing, what would happen to the acceleration of the cart? Explain your answer using Newton's Second Law.
Answer:
The acceleration will decrease/reduce
Explanation:
Newton in his second law of motion states that the acceleration of an object is dependent on the force and mass applied on the object. Using the equation as follows:
F = m × a
Where;
F = force (N)
m = mass (kg)
a = acceleration (m/s²)
Acceleration (a) is directly proportional to the force (F) applied but inversely proportional to the mass (m).
According to this question, a friend drops 50 pounds of dog food into a cart being pushed with speed. This means that the mass/weight of the cart was increased. Since the acceleration is inversely proportional to the mass of an object, this means that the acceleration of the cart will DECREASE/REDUCE as the mass increases.
Một dây nhôm dài 10 m khi ở 25 độ C. Biết khi nhiệt độ tăng thêm 1 độ C thì chiều dài 1m dây nhôm sẽ tăng thêm 0,024mm.
a) Tính ăng chiều dài của 1m dây nhom khi nhiệt độ tăn thêm 75 độ C
b) Tính chiều dài dây nhôm ở 75 độ C
Answer:
??????? what language is this. um A then
How long can a tow rope or chain be?
1. 20 feet 2. 15 feet
3. 5 feet
4. 10 feet
Answer:
"For towing, a tow chain should be of a length that keeps both vehicles within the maximum 4.5 meter distance, also tow chains an be any length 20 foot chains are often chosen"
Explanation:
- https://letstowthat.com
Also Quick note the feet of tow rope or chain varies on the situation but most longest or 20 feet.
An empty cardboard box falls from a high platform. Through the use of special equipment it was found that the energy of the cardboard box at the top of the fall was more than the energy of the box at the bottom of the fall. Explain.
Answer:
The mechanical energy of the cardboard box, M.E. = K.E. + P.E.
Where;
P.E. = The potential energy of the cardboard box = m·g·h
K.E. = The kinetic energy of the cardboard box = (1/2)·m·v²
Where;
m = Mass of the cardboard box
g = The (constant) acceleration due to gravity ≈ 9.81 m/s²
h = The height of the cardboard box
v = The velocity of the cardboard box
At the top of the fall, where h = The height of the platform = [tex]h_{platform}[/tex], and v = 0 (the box is initially at rest at the top), the M.E. is given as follows;
[tex]M.E._{top}[/tex] = P.E. + K.E. = m·g·[tex]h_{platform}[/tex] + (1/2) × m × 0² = m·g·[tex]h_{platform}[/tex]
However, at the bottom of the fall, the height of the box, h = 0, the velocity of the box, v = 0, therefore, the total energy at the bottom, after the box comes to rest, [tex]M.E._{bottom}[/tex] = 0
Therefore;
The total energy of the box at the top of the fall, .[tex]M.E._{top}[/tex] = m·g·[tex]h_{platform}[/tex] was more than the total energy of the box at the bottom of the fall,
[tex]M.E._{bottom}[/tex] = 0
Explanation:
Which of the following changes would not lead to changes in the efficiency of
a heat engine?
A. Doubling the work done while keeping the heat flow into the
engine the same
B. Doubling the heat flow into the engine while halving the work done
C. Doubling both the work done and the heat flow into the engine
D. Doubling the heat flow into the engine while keeping the work
done the same
Explanation:
B. Doubling the heat flow into the engine while halving the work done
hope this helps you
have a nice day
como previene un diafragma el embarazo
Answer:
Un diafragma es una pieza de silicona o de goma reutilizable que cubre el cuello del útero. El diafragma se coloca dentro de la vagina con espermicida antes de tener relaciones sexuales para prevenir un embarazo. El diafragma es un dispositivo anticonceptivo que impide que los espermatozoides ingresen en el útero.
out of solid and liquid which has more effect on gravitation
Answer:
The effect of gravitation is more in liquid than on solid because inter molecular force of attraction is less in liquid and it is weak than that of solid. ... Whereas in solid the molecule are densely packed together an the inter molecular forces are constantly acting upon one another, this results in higher forces.
The distance a cart moves down a track (from rest) is proportional to the time squared. How far would a cart move down a track (from rest) in two seconds if it moves (from rest) a distance of 20 cm in one second?
A) 5 cm B) 10 cm C) 20 cm D) 40 cm E) 80 cm
A car move down a track a distance of 80 cm
Letter E 80 cm
Proportional
if the distance is proportional to the time square we can express such condition writing
d = k*t² (1)
where d is the distance t is the time and k is the constant of proportionality.
Now we must considerer that if the cart moves a distance of 20 cm in one second then by substitution in equation (1)
20 = k * (t)² ⇒ 20 = k*1 then k = 20
The proportionality constant is K = 20
To determine how far the cart move down in 2 seconds, again by substitution in equation (1) ( but now knowing k )
d = 20*(2)²
d = 20*4
d = 80 cm
There are four charges, each with a magnitude of 4.25 C. Two are positive and two are negative. The charges are fixed to the corners of a 0.440-m square, one to a corner, in such a way that the net force on any charge is directed toward the center of the square. Find the magnitude of the net electrostatic force experienced by any charge.
Answer:
F = 7.68 10¹¹ N, θ = 45º
Explanation:
In this exercise we ask for the net electric force. Let's start by writing the configuration of the charges, the charges of the same sign must be on the diagonal of the cube so that the net force is directed towards the interior of the cube, see in the attached numbering and sign of the charges
The net force is
F_ {net} = F₂₁ + F₂₃ + F₂₄
bold letters indicate vectors. The easiest method to solve this exercise is by using the components of each force.
let's use trigonometry
cos 45 = F₂₄ₓ / F₂₄
sin 45 = F_{24y) / F₂₄
F₂₄ₓ = F₂₄ cos 45
F_{24y} = F₂₄ sin 45
let's do the sum on each axis
X axis
Fₓ = -F₂₁ + F₂₄ₓ
Fₓ = -F₂₁₁ + F₂₄ cos 45
Y axis
F_y = - F₂₃ + F_{24y}
F_y = -F₂₃ + F₂₄ sin 45
They indicate that the magnitude of all charges is the same, therefore
F₂₁ = F₂₃
Let's use Coulomb's law
F₂₁ = k q₁ q₂ / r₁₂²
the distance between the two charges is
r = a
F₂₁ = k q² / a²
we calculate F₂₄
F₂₄ = k q₂ q₄ / r₂₄²
the distance is
r² = a² + a²
r² = 2 a²
we substitute
F₂₄ = k q² / 2 a²
we substitute in the components of the forces
Fx = [tex]- k \frac{q^2}{a^2} + k \frac{q^2}{2 a^2} \ cos 45[/tex]
Fx = [tex]k \frac{q^2}{a^2}[/tex] ( -1 + ½ cos 45)
F_y = k \frac{q^2}{a^2} ( -1 + ½ sin 45)
We calculate
F₀ = 9 10⁹ 4.25² / 0.440²
F₀ = 8.40 10¹¹ N
Fₓ = 8.40 10¹¹ (½ 0.707 - 1)
Fₓ = -5.43 10¹¹ N
remember cos 45 = sin 45
F_y = - 5.43 10¹¹ N
We can give the resultant force in two ways
a) F = Fₓ î + F_y ^j
F = -5.43 10¹¹ (i + j) N
b) In the form of module and angle.
For the module we use the Pythagorean theorem
F = [tex]\sqrt{F_x^2 + F_y^2}[/tex]
F = 5.43 10¹¹ √2
F = 7.68 10¹¹ N
in angle is
θ = 45º
Is velocity ratio of a machine affected by applying oil on it?Explain with reason.
Answer:
It depends upon SAE No. of oil. (SAE means Society of Automotive Engineers). However, it usually does protect against friction.
Explanation:
If we use very viscous oil, it does not reach all the parts. Very thin oil will flows away easily and gets wasted. Grease is used in such cases. It is generally used around ball-bearing. Normal grease or oil is never used where there is high pressure, high temperature and high speed. Special lubricants are used in such cases. In cold season the oil becomes thick and in hot season it becomes thin. Therefore selection of lubrication also depends on the season. It is always advisable to refer operating manual of the equipment before selecting the lubricant.
The intensity of friction depends on following factors:
i) The area involved in friction.
ii) The pressure applied on the surfaces.
Force = Pressure ´ Area Frictional force will increase, if the area of contact will increase or if pressure applied on the surface increased.
A cricket ball of mass 800g has momentum of 20 kg m/sec . Calculate velocity of ball
Answer: 25 m/s
Explanation:
1. rearrange equation p = mv to find v
2. v = p/m - then convert 800 g into kg (= 0.8 kg)
3. plug in p and m - v = 20 / 0.8 = 25 m/s
Answer:
V= 25m/s
Explanation:
Mass=800g
Momentum=20kgm/s
V= ?
Convert 800g to kg
800/1000 = 0.8kg
Momentum=mass× Velocity
Momentum/Mass = Velocity
20/0.8 =25m/s
Muốn đun sôi 200g nước từ 30 độ cần cung cấp nhiệt lượng bao nhiêu :
Answer:
cần cung cấp 70 độ vì nước sôi ở 100°C
Explanation:
We use __force to do different force. 1) pulling 2)pushing 3)gravity 4)muscular
Answer:
gravity
Explanation:
We use gravity to do different force.
Một người đi xe ô tô từ a đến b cách nhau 90km trong nửa quãng đường đầu người dó đi với vận tốc v1 trong nửa quãng đường sau người đó đi với vận tốc v2=2v1/3.Tính vận tốc của người đó trên mỗi chặng đường để sau 1.5h người đó đi đến b
Answer:
The speed of the first half is 75 km/h and for the second half is 50 km/h.
Explanation:
A person driving a car from a to b 90km apart for the first half of the distance travels with speed v1 the second half of the distance travels with a speed of v2=2v1/3. Calculate his speed per each the distance so that after 1.5 hours that person reaches b
Total distance, D = 90 km
Let the time for he first half is t and for the second half is t'.
Distance = speed x time
45 = v1 x t .... (1)
And
45 = v2 x t' .... (2)
Total time is T = t + t'
[tex]1.5 = \frac{45}{v_1}+\frac{45}{v_2}\\\\1.5 = \frac{45}{v_1}+\frac{3\times 45}{2v_1}\\\\1.5 = \frac{90+135}{2v_1}\\\\3v_1 = 225 \\\\v_1 = 75 km/h[/tex]
Now, v2 = 2 x 75/3 = 50 km/h
A. Tick (1) the best alternatives. 1. What is the acceleration due to gravity on the surface of moon ? (a) 9.8m/s (b)1.6m/s2 (c) 6.67x10-1m/s (d) 9.8m/s?
Answer:
[tex] \green{ \sf \: \: 1.6 \: m {s}^{ - 2} \: \: \: is \: the \: correct \: answer}[/tex]
Explanation:
[tex] \sf \: \huge{g } _{ \small{moon}} = \frac{ {\huge{g}}_{earth}}{6} \\ \\ \sf \implies \: \sf \: \huge{g } _{ \small{moon}} = \frac{ 9.8}{6} = 1.6 \: \: m {s}^{ - 2} [/tex]
A bucket filled woth water seems light while it sinks into water.Also show their relation using formula
Answer: This phenomenon happens due to upthrust exerted by water.
Explanation:
We know that,
Liquid Pressure is directly proportional to the height of the vertical column in the liquid.(P∝h)
When a bucket filled water is sunk into the water container, there occur difference in the pressure in top and bottom of the water container. Due to this, water exerts an upward force on the bucket filled with water. This is called Uprthrust.
Upthrust on the bucket makes the bucket filled with water lose some of it's weight and causes apparent loss in weight.
Hence, the bucket filled with water seems light while it sinks into water.
The direction of applied force has to be .............. to the distance in order to say work is done
Answer:
Parallel
Explanation:
The work done is defined as the force applied on an object and the displacement in the position of the object in the direction of force.
W = F s cos A
where, F is the force, s is the displacement and A is the angle between force and displacement.
When the angle between the force and the displacement is 90 degree, the work done is zero.
To get the maximum work the angle between the force and the displacement is 0 degree.
So, to get the work done by the force the angle between the force and displacement is 0 degree that means the force and displacement is parallel to each other.
