the outer shell of the star are blown off with big clouds of gas and dust which is know as a nebula
the change in resistance of a metallic conductor at temperature below 0°C is
A. Linear
B. Non linear
C. Curve
D. Curvilinear
Answer:
A: Linear
Explanation:
Formula for Resistance of a metallic conductor is given as;
R = R_o(1 + αΔT)
Where;
R_o is the original resistance
R is the final resistance after change in temperature
ΔT is change in temperature
α is coefficient of linear expansion
Now, from the formula given, we can see that the change in resistance is directly proportional to the change in temperature.
Thus, the higher the final temperature, the more the change in resistance and the lower the final temperature, the lesser the change in resistance.
Thus, for temperature less than zero, since the change is resistance is directly proportional to the temperature, it means it follows a linear relationship.
You stand on a merry-go-round which is spinning at f = 0.25 revolutions per
second. You are R = 200 cm from the center.
(a) Find the angular speed ω at which it is spinning.
[3 marks]
(b) Find the centripetal acceleration, ac with which it is spinning. [3 marks]
(c) What is the minimum coefficient of static friction µs between your shoes and
the floor that will keep you from slipping off?
[4 marks]
Answer:
(a) ω = 1.57 rad/s
(b) ac = 4.92 m/s²
(c) μs = 0.5
Explanation:
(a)
The angular speed of the merry go-round can be found as follows:
ω = 2πf
where,
ω = angular speed = ?
f = frequency = 0.25 rev/s
Therefore,
ω = (2π)(0.25 rev/s)
ω = 1.57 rad/s
(b)
The centripetal acceleration can be found as:
ac = v²/R
but,
v = Rω
Therefore,
ac = (Rω)²/R
ac = Rω²
therefore,
ac = (2 m)(1.57 rad/s)²
ac = 4.92 m/s²
(c)
In order to avoid slipping the centripetal force must not exceed the frictional force between shoes and floor:
Centripetal Force = Frictional Force
m*ac = μs*R = μs*W
m*ac = μs*mg
ac = μs*g
μs = ac/g
μs = (4.92 m/s²)/(9.8 m/s²)
μs = 0.5
You accidentally drop a watch from the roof of a six-story building. While picking up the watch , you notice that it stopped 2s after it was dropped. How tall is the building?
Answer:
20 m
Explanation:
Area under the speed-time graph = Distance Traveled
Area under Graph 1/2(2)(20)
=20 m
A radioactive atom has just undergone nuclear decay. Its mass number is now four less than the original atom. Which type of nuclear decay has occurred?
Answer:
Explanation:
mass number is now 4 times less than the original value so alpha decay occur during alpha decay the mass number is decreased 4 times and atomic number decreased 2 times than the original value
The pupil of a cat's eye narrows to a slit width of 0.5 mm in daylight. What is the angular resolution of the cat's eye in daylight (wavelength = 500 nm)?
A. 0.01 rads
B. 10-5 rads
C. 10-3 rads
D. 10-4 rads
Answer:
C. 10⁻³ rads
Explanation:
Here, we shall use Rayleigh's Criterion to find out the angular resolution of Cat's eye during day light. Rayleigh's Criterion is written as follows:
θ = λ/a
where,
θ = angular resolution of Cat's eye = ?
λ = wavelength = 500 nm = 5 x 10⁻⁷ m
a = slit width of eye = 0.5 mm = 5 x 10⁻⁴ m
Therefore,
θ = (5 x 10⁻⁷ m/5 x 10⁻⁴ m)
Therefore,
θ = 0.001
θ = Sin⁻¹(0.001)
θ = 0.001 rad = 1 x 10⁻³ rad
Hence, the correct answer is:
C. 10⁻³ rads
what is the mass of the 40 kg object on the moon?
Answer:
6.64 Newtons
On the moon that 40 kg child would have a weight of 6.64 Newtons (kg multiplied by gravity) because the moon's gravity is 1/6th of the Earth's gravity. Your mass on any planet on the solar system (Jupiter, Venus, Earth, or anywhere else) is the same because the amount of matter in you does not change.
Explanation:
An object of mass 3.4 kg is moving in a straight line with kinetic energy 59.177 J. A force is applied in the direction of its motion for 2.7 seconds, and as a result, its kinetic energy is multiplied by a factor of 1.57. By what factor is its momentum multiplied?
Answer:
Its momentum is multiplied by a factor of 1.25
Explanation:
First, we calculate the initial velocity of the object:
K = 0.5 * m * v₁²59.177 J = 0.5 * 3.4 kg * v₁²v₁ = 5.9 m/sWith that velocity we can calculate the initial momentum of the object:
p₁ = v₁ * mp₁ = 20.06 kg·m/sThen we calculate the velocity of the object once its kinetic energy has increased:
(59.177 J) * 1.57 = 0.5 * 3.4 kg * v₂²v₂ = 7.4 m/sAnd calculate the second momentum of the object:
p₂ = v₂ * mp₂ = 25.16 kg·m/sFinally we calculate the factor:
p₂/p₁ = 1.25Sully is riding a snowmobile on a flat, snow-covered surface with a constant velocity of 10 meters/second. The total mass of the snowmobile, including Sully, is 280 kilograms. If Sully accelerates to a velocity of 16 meters/second over 10 seconds, what’s the force exerted by the snowmobile to accelerate? Use F = ma, where . A. 160 N B. 168 N C. 248 N D. 280 N E. 324 N
Answer:
280.6N
Explanation:
According to Newton's second law;
Force = mass * acceleration
Given
Mass = 280kg
velocity = 10m/s
Time = 10 secs
Acceleration = velocity?/Time
Force = mass * velocity/time
Force = 280 + (16-10/10)
Force = 280 + 0.6
Force = 280.6N
Hence the force exerted by the snowmobile to accelerate is 280.6N
Answer:168 N
Explanation:
Give one suggestion how to increase the velocity of water rocket?
Answer:
Streamline the body of the rocket to reduce drag
Keep weight to a minimum
Use higher pressures
Use the right amount of water
Much of the energy of falling water in a waterfall is converted into heat. If all the mechanical energy is converted into heat that stays in the water, how much of a rise in temperature occurs in a 111 m waterfall?
Answer:
Explanation:
potential energy of water is converted into heat energy
P E = mgh = m x 9.8 x 111
= 1087.8 m .
Let rise in temperature θ
m x s x θ = heat absorbed
m x s x θ = 1087.8 m
m x 4182 x θ = 1087.8 m
θ = 0.26 degree celsius .
How long would it take light to travel round trip to Mars when it is 2x1010m from the Earth?
a) 0.015s
b) 0.03s
c) 66.7s
d) 133s
Show calculation
Answer:
66.7s
Explanation:
Given parameters:
Distance between Mars and Earth = 2 x 10¹⁰m
Unknown:
Time it takes for light to travel = ?
Solution:
The speed of light is given as 3 x 10⁸m/s
Now;
Speed = [tex]\frac{distance}{time}[/tex]
Time = [tex]\frac{distance}{speed}[/tex]
Insert the parameters and solve;
Time = [tex]\frac{2 x 10^{10} }{3 x 10^{8} }[/tex] = 66.7s
given a circuit powered at 12V with R1, R2, R3 respectively of 10,20,30 Ohm, determine R4 in such a way that the Wheatstone bridge is in equilibrium and then calculate voltages and currents as for reference exercise.
Answer:
The balanced condition for Wheatstones bridge is
Q
P
=
S
R
as is obvious from the given values.
No, current flows through galvanometer is zero.
Now, P and R are in series, so
Resistance,R
1
=P+R
=10+15=25Ω
Similarly, Q and S are in series, so
Resistance R
2
=R+S
=20+30=50Ω
Net resistance of the network as R
1
and R
2
are in parallel
i=
R
V
=
50
6×3
=0.36 A.
Explanation:
A block of mass 500g is pulled from rest on ahorizontal frictionless bench by a steady force F and travels 8m in 2s find the acceleration?
We are Given:
Mass of the block (m) = 500 grams or 0.5 Kg
Initial velocity of the block (u) = 0 m/s
Distance travelled by the block (s) = 8 m
Time taken to cover 8 m (t)= 2 seconds
Acceleration of the block (a) = a m/s²
Solving for the acceleration:
From the seconds equation of motion:
s = ut + 1/2* (at²)
replacing the variables
8 = (0)(2) + 1/2(a)(2)²
8 = 2a
a = 4 m/s²
Therefore, the acceleration of the block is 4 m/s²
Net force causes motion.
Answer: If you want me to write them for you here they are
Explanation:
Net force causes change in motion because a net external force causes a change in motion; thus, we see that a net external force causes acceleration.
Not more likely to be Net force motion because if it doesnt say change then its gonna stay the same so Net force does cause change in a motion because take for example if you are going to bounce a basketball its gonna change its position from one place to another thats how Net force causes Change in motion.
Hope this helps :)
A projectile is launched straight upward at 50 m/s. Neglecting air resistance its speed upon returning to its starting point is:________.
Answer:
The speed of the projectile upon returning to its starting point is 50 m/s.
Explanation:
Given;
initial velocity of the projectile, u = 50 m/s
The velocity of the projectile is maximum before hitting the ground. As the object moves upward, the velocity reduces as it approaches the maximum height, at the maximum height the velocity becomes zero. Also, as the object moves downward, the velocity starts to increase and becomes maximum before hitting the ground.
Therefore, the speed of the projectile upon returning to its starting point is 50 m/s.
What are some tasks that organelles perform inside of a cell?
Answer:
Different organelles play different roles in the cell — for instance, mitochondria generate energy from food molecules; lysosomes break down and recycle organelles and macromolecules; and the endoplasmic reticulum helps build membranes and transport proteins throughout the cell.
Explanation:
Hopefully this helped!
which of the following calls one might hear a refree make?
A) Strike
B) Foul
C) Safe
D) All of the above
Answer: D) All of the above
Explanation:
An 11-kilogram cart is pulled with a horizontal force at a constant velocity of 8.0 meters per second, as shown in the diagram. The force of friction between the cart and the floor is 12 newtons. What is the magnitude of the horizontal force?
The cart is pulled at a constant velocity, so it is in equilibrium. In particular, the net horizontal force is zero, and consists of only the pulling force and friction such that
p - f = 0
where p and f denote the magnitudes of the pulling force and friction.
So we have
p - 12 N = 0
p = 12 N
Is a light bulb that is off potential energy or kinetic energy?
An astronaut weighs 626 newtons at Earth's surface. If he were to cut his distance from
Earth's center in half, what would be his new weight, to the nearest newton?
Kate is creating two models to describe the effect of thermal energy on the movement of particles in a liquid. She draws the first model of a liquid sample. Her model is shown below.
Explanation:
so sorry
don't know but please mark me as brainliest please
To overcome an object's inertia, it must be acted upon by __________. A. gravity B. energy C. force D. acceleration
A car is initially moving at 100 m/s and decides to gun it. They accelerate at a rate of 20 m/s/s for 10 seconds. How far did they travel during this time period?
Answer:
dx = 2000 [m]
Explanation:
To solve this problem we must use the following equation of kinematics.
[tex]dx =v_{o}*t +\frac{1}{2} *a*t^{2}[/tex]
where:
dx = distance [m]
Vo = initial velocity = 100 [m/s]
a = acceleration = 20 [m/s²]
t = time = 10 [s]
dx = 100*10 + 0.5*20*10²
dx = 2000 [m]
Note: the positive sign in the above equation means that the car is increasing its velocity.
A wooden block contains some nails so that its density is exactly equal to that of water. If it is placed in a tank of water and released from rest when it is completely submerged, it will:_____.a. remain where it is released. b. rise to the surface. c. sink to the bottom.
Answer:
The correct answer is:
a) remain where it is released
Explanation:
The concept of density seeks to measure the weight of an object in relation to its size. It is the measure of how packed together the particles of that object are. An object placed in a liquid displaces a certain volume of the liquid, based on the relative density of the object and the liquid.
If an object is less dense than a liquid in which it is placed, it displaces a smaller volume of the liquid than its volume, hence only some part of the object will be seen to be under the liquid, the other part will float.
If an object is denser than the liquid in which it is placed, it displaces a larger volume of the liquid than its own volume, making the object to sink and is submerged, sometimes to the bottom of the liquid, but mostly below the point at which it was released.
Finally, if the density of an object and the liquid into which it is submerged is the same. the object's mass per unit volume is the same as the liquid's mass per unit volume, hence the weight and force created due to density will balance and cancel each other out hence making the object to remain where it was submerged.
Dos niños sostienen una piñata cuyo peso es de 196N, formando un ángulode 140°con ambas cuerdas. Calcular la fuerza aplicada por cada niño
Answer:
T = 104.2 N
Explanation:
For this exercise we must define a coordinate system, the x axis is horizontal and the y axis is vertical, let's write the equilibrium equations on each axis
X axis
T₁ₓ-T₂ₓ = 0
T₁ₓ = T₂ₓ (1)
y axis
[tex]T_{1y}[/tex] + T_{2y} - W = 0
T_{1y} + T_{21y} = W (2)
Let's use trigonometry to find the decomposition of the stresses, they indicate that the angle between the two forces is 140º, but each force has an angle of 70º
cos 70 = T₁ₓ / T₁
T₁ₓ = T₁ cos 70
sin 70 = [tex]T_{1y}[/tex] / T₁
T_{1y} = T₁ sin 70
for tension 2 we have a similar equation
T₂ₓ = T₂ cos 70
T_{2y} = T₂ sin 70
From equation 1
T₁ cos 70 = T₂ cos 70
T₁ = T₂
therefore the two children apply the same force
From equation 2
T sin 70 + T sin 70 = W
2 T sin 70 = W
T = W / 2sin 70
T = 196 / (2 sin 70)
T = 104.2 N
the two children have the same strength
What happens when a charged balloon is brought close to a wall?
The balloon becomes negatively charged.
The charges in the wall rearrange themselves.
The wall and the balloon repel each other.
The wall becomes negatively charged.
Answer:
a the balloon becomes negatively charged
When a charge balloon brought closer to the wall, they will repel each other. Option C is correct.
Electric Charge:
It shows the degree at which the atom or object has less or more electron than proton.
An atom with extra electrons than proton has negative charge while atoms will less electron than proton has positive charge.
Opposite charge always attracts while similar charges repel each other. Since both wall and balloon are negatively charged.
Therefore, when a charge balloon brought closer to the wall, they will repel each other.
To know more about Electric Charge:
https://brainly.com/question/8163163
In a block-spring system
m = 0.25kg
and
k = 4N /m
. At
t = 0.15s
, the velocity is
v = −0.174m/s
and
the acceleration
2
a = +0.877m /s
. Write an expression for the displacement as a function of time,
x(t)
Answer:
the answer is b
Explanation:
An expression for the displacement as a function of time is x(t) = a sin wt.
What is Displacement?Displacement is defined as the change in position of an object. It is a vector quantity and has a direction and magnitude. The spacing between two specified points is represented by displacement, a one-dimensional measure commonly known as length or distance.
Given in the question we have to find the displacement of the as function of time
The equation used of express displacement is.
d = V i t + 1 2 a t 2
Displacement = Final position – initial position = change in position.
so, x = A sin wt is equation where A is amplitude and t is time period.
An expression for the displacement as a function of time is x(t) = a sin wt.
Thus, an expression for the displacement as a function of time is x(t) = a sin wt.
To learn more about displacement refer to the link:
brainly.com/question/11934397
#SPJ2
Select the correct answer from each drop-down Box menu Debbie places to shopping carts in a car corral she pushes the first car which then pushes a second car what force is being exerted Debbie exerts blank force on the first shopping cart the first card exerts blank force on the second card
Answer: Debbie exerts applied force on the first cart.
Explanation:
The first cart exert applied force on the second cart.
How much work is done when you push a table with 300 N of force 5 m across a room?
PLEASE IM TIMED
If total mechanical energy = kinetic energy + potential energy, TME = KE + PE, and a roller coaster has 500 J of total mechanical energy. At the very beginning of the track the roller coaster has 500 J of potential energy, how much kinetic energy is there at the beginning of the track?
Answer:
As already mentioned, the mechanical energy of an object can be the result of its motion (i.e., kinetic energy) and/or the result of its stored energy of position (i.e., potential energy). The total amount of mechanical energy is merely the sum of the potential energy and the kinetic energy.
Explanation:
