When asked to name all the forces on a marker sitting in equilibrium on a desk, a student responds: “Since the marker on the desk is at rest, there are no forces
acting on it.” Why is this wrong? How would you restate it?
Answer:
The forces acting on the pen which is still on the table can have two forces acting on them. The forces are gravitational force and the equal and opposite force to the gravitational forces.
The equal and opposite forces that is applied on the pen keeps the pen still on the table.
So, the statement that no force is applied on the pen which is kept still on the table is wrong as two forces are applied on the pen.
As both the forces are equal and opposite so it is cancelled and is still.
Calculate the amount of energy transferred when a 40w light bulb is left on for 30 minutes.
Answer:
E=72000J or 72kj
Explanation:
The formula is E=pt you need to convert your t from minutes to seconds before proceeding
Answer!!!!!!!!!!!!!!!!!!!!
Acceleration =change in velocity÷Time taken
or, Acceleration =final velocity-Initial velocity÷Time taken
or, a=v-u÷t
or, at=v-u
or, v-u=at
therefore, v=u+at
The sputnik one satellite orbiting earth mass equals 5.98×10 to the 24th power kilograms in a circle of radius 6.96×10 to the six power meters what was its orbital velocity
Answer:
7572 m/s
Explanation:
The force between two masses separated by a distance r is given as:
[tex]F=G\frac{m_1m_2}{r^2}[/tex]
Where F is the attractive force between 2 masses, m1 and m2, r is the distance between the centres of the masses and G is the universal gravitation constant, which is [tex]6.674*10^-11 Nm^2/kg^2[/tex]
The mass of the earth ([tex]m_1[/tex]) is far greater than the mass of the sputnik ([tex]m_2[/tex]). Therefore [tex]m_1m_2=m_1[/tex]. The mass of the sputnik is neglected, therefore:
[tex]F=G\frac{m_1}{r^2}=\frac{(6.674*10^{-11})(5.98*10^{24})}{(6.96*10^6)^2} = 8.2389N[/tex]
But F is actually centripetal acceleration, a = v²/r
[tex]8.2389 = v^2 / 6.96*10^6\\v=7572m/s[/tex]
state newtons second law of motion from the equation f: ma
Newton's Second Law of Motion states "The rate of change of momentum of a body is directly proportional to the applied unbalanced force in the direction of force".
What is the SI unit used to measure force?
Newton
Meter
Pascal
Joule
Answer:
newton(N)
Explanation:
if a 10 kg object has a kinetic energy of 20 J what is its speed and what is the formula used to calculate speed
Answer:
2 meter per second
Explanation:
kinetic energy = 1/2 m v^2
20J = 1/2 × 10 × v^2
v^2 = 4
v= 2 m/s
PLEASE HELP
GREATLY APPRECIATED IF YOU DO
Answer:
a. 38400j
Explanation:
p= mgh
2400×10×1.6
A 38.5 kg man is in an elevator
accelerating downward. A normal
force of 343 N pushes up on him.
What is his acceleration?
Answer:
F = m*(g - a) →
a = g - F/m = 0.891 m/s² downward
Explanation:
If elevator was stationary, the normal force of elevator floor on man* would be = mg
mg = (38.5)(9.81) ≈ 378 N.
If elevator is accelerating downward the floor is accelerating away from man and so the normal force will be less than man's weight by: 378 - 343 = 35 N.
Hope this helps.
Answer:
-0.891
Explanation:
negative because downward
Gold has a density of 19300 kg/m³. Calculate the mass of 0.02 m³ of gold in kilograms.
Answer:
Mass = 386 kg
Explanation:
Density = Mass / Volume
Mass = Density × Volume
Where D = 19300 kg/m³ , V = 0.02 m³
Putting the given in the above formula
Mass = 19300 × 0.02
Mass = 386 kg
Answer:
386 kg
Explanation:
mass = density * volume
= 19300 * 0.02
= 386 kg
Hope this helps!
if a ray of light is incident on plane mirror at an angle of 300 its angle of reflection is.
Answer:
300°
Explanation:
both the angles of incidence and reflection are the same
A 2.0 g ball with a +0.05 C charge is moved from the negative plate to the positive plate, and then is released. The potential difference between the plates is 12.0V. When the ball strikes the (–) plate its velocity is most nearly equal to
Answer:
24.5 m/s
Explanation:
Since the work done by the electric field on the charge equals the kinetic energy of the ball, then
qV = 1/2mv²
and v = √(2qV/m)
where q = charge = + 0.05 C, V = potential difference = 12.0 V, m = mass of ball = 2.0 g = 0.002 kg
Substituting the values into v, we have
v = √(2 × + 0.05 C × 12.0 V/0.002 kg)
= √(1.2 CV/.002 kg)
= √(600 CV/kg)
= 24.5 m/s
If an object is thrown up at an initial velocity of 9.8 m/s, how long will it take to fall back to the ground?
What is the frequency of a wave if 10 waves go past in 1 second ?
Answer:
f = 10 Hz
Explanation:
We need to find the frequency of a wave if 10 waves go past in 1 second. Total number of waves per unit time is called frequency. So,
[tex]f=\dfrac{10}{1}=10\ Hz[/tex]
So, the frequency of a wave is 10 Hz.
Date
Page
710
Amachine raises a load of 750N
through a height
of 16m in 5 sec
calculate
a) work done by machine
b) Power of machine
Answer:
W=F×H,Power=W/Time
Explanation:
W=Force ×Height
750N×16 =12000
Power=Work/Time
12000/5=2400J
If the distance is halved and the charges of both particles are doubled, the force is ________ as great.
Answer:
The new force is 16 times of the initial force.
Explanation:
The electric force between charges is given by :
[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]
If the distance is halved, d' =d/2 and charges are doubles, [tex]q_1'=2q_1\ \text{and}\ q_2'=2q_2[/tex]
New force becomes,
[tex]F'=\dfrac{kq_1'q_2'}{r'^2}\\\\F'=\dfrac{k(2q_1)(2q_2)}{(d/2)^2}\\\\F'=16\times \dfrac{kq_1q_2}{r^2}\\\\F'=16F[/tex]
So, the new force is 16 times of the initial force.
If the distance is halved and the charges of both particles are doubled, the force is 16 times as great.
Coulomb's LawAccording to Coulomb's law, the electrostatic force between two charges is given by;
[tex]F=k\frac{q_1 q_2}{r^2}[/tex]
Where 'k' is the Coulomb's constant.
If the charges of both particles are doubled and the distance is halved, the new force will be;
[tex]F\,'=k\frac{2q_1 \times 2q_2}{(r/2)^2}=k \frac{4\times 4\times q_1 q_2}{r^2} =16\,F[/tex]
So, the new force will be 16 times greater than the old force.
Learn more about Coulomb's law here:
https://brainly.com/question/14049417
A body of mass 1kg has a 25kgsmsqure moment of inertia about its center of mass. if it rotated about an axis which has a displacement (5,12)m, its moment of inertia about this axis becomes
Answer:
194 kg m²
Explanation:
Use parallel axis theorem:
I = I₀ + mr²
I = 25 kg m² + (1 kg) ((5 m)² + (12 m)²)
I = 25 kg m² + 169 kg m²
I = 194 kg m²
A car travels 20 miles in 1 hour 15 minutes. What is its average speed
If a car travels 20 miles in 1 hour and 15 minutes, then the average speed of the car would be 7.15 meters/second.
What is speed?The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object.
As given in the problem, if a car travels 20 miles in 1 hour and 15 minutes, then we have to find the average speed of the car,
1 mile = 1609 meters
20 miles = 20*1609 meters
= 32180 meters
1 hour = 3600 seconds
1 minutes = 60 seconds
15 minutes = 15*60
=900 seconds
1 hour and 15 minutes = 4500 seconds
The average speed of the car = The distance traveled by car/time
= 32180 meters / 4500 seconds
= 7.15 meters / seconds
Thus, the average speed of the car would be 7.15 meters/second.
To learn more about speed from here, refer to the link;
brainly.com/question/7359669
#SPJ2
which atomic particle has no charge?
A. Electron
B. Neutron
C. Nucleus
D. Proton
Answer:
B. Neutron has no charge
Answer:
B. Neutron
Explanation:
Firstly, the nucleus is what contains the protons and electrons, so it is not an atomic particle. The electron has a negative charge, and the proton has a positive charge (you can remember this by looking at its prefix 'pro'). This means the neutron has no charge (think of it as neutral).
Please Hurry!! This is very simple!
What are your thoughts about the connection between exercise and memory? How often do you exercise? Do you exercise more or less now that you are no longer on campus? Is that a good or bad thing? Why?
Answer:
What are your thoughts about the connection between exercise and memory?
I think its important to memorize how much u work out and exersize. make sure u dont do it too much or u might pass out. keep track of ur health by memorizing what u ate and when u ate before doing a lot of movement. you might throw up. Exercising is obviously very important for your body.
How often do you exercise?
5 times a week. (5/7 days)
Do you exercise more or less now that you are no longer on campus? Is that a good or bad thing?
A little less. But i think its a good thing
Why?
I used to go to a gym near campus! But now some are a little farther but during this time of quarantine, i work out at home and do the basics like running and agility. I think its good because it teaches me the exercising i can do at home instead of getting memberships and using my money. now i can spend money wisely and still exersize.
Mark as brainliest!
hope this helps! :)
make any changes if ud like
Explanation:
if it takes 20 n to move an object 20m how much work was done
Answer:
[tex]\boxed{Work \: done = 400 \: N-m}[/tex]
Explanation:
Force = 20 N
Displacement =20 m
Work Done = Force × Displacement
= 20 × 20
= 400 N-m
What change occurs to the gravitational force of attraction between two bodies when the
distance between them is made half (1/2) by keeping masses constant?
Answer:
when the radius is halved, F becomes 4 times
Explanation:
The formula is given by
[tex]F = \frac{Gm1m2}{r^2}[/tex]
When r is halved:
[tex]F = \frac{Gm1m2}{(1/2r)^2}[/tex]
=> [tex]F = \frac{Gm1m2}{1/4 r^2}[/tex]
=> [tex]F = 4(\frac{Gm1m2}{r^2} )[/tex]
This means when the radius is halved, F becomes 4 times
Sobre un velero actúa la fuerza del motor de 900 N y perpendicularmente a ella, la del viento de 750 N. Si se mueve con MRU, ¿qué fuerza de rozamiento actúa sobre el barco?
Answer:
[tex]F=F_{f}=1171.5 N[/tex]
Explanation:
We know that the sailboat has a uniform movement, therefore the total force, the engine, and the wind must be equal to the friction force.
[tex]F=F_{f}[/tex]
[tex]F=F_{f}=\sqrt{F^{2}_{engine}+F^{2}_{wind}}[/tex]
[tex]F=F_{f}=\sqrt{900^{2}+750^{2}}[/tex]
[tex]F=F_{f}=1171.5 N[/tex]
Therefore the friction force is 1171.5 N.
I hope it helps you!
Write a statement about your understanding of how momentum is conserved during a collision
when a body of mass 0.25kg is acted upon by a force, the velocity changes from 5m/s to 7.5m/s. Calculate the work done by the force
Answer:
Work done by the force = 1/2m×(v2 - v1)²
m = mass
v2 = final velocity
v1 = initial velocity
= 1/2(0.25)(7.5-5)²
= 1/2(0.25)(2.5)²
= 1/2(0.25)(6.25)
= 0.78J
Hope this helps.
3.
A body starts moving from rest and attains the acceleration of 0.5 m/s2. Calculate the
velocity at the end of 3 minutes and also find the distance travelled by it during that
time.
Answer:
90 m/s
8100 m
Explanation:
Given:
v₀ = 0 m/s
a = 0.5 m/s²
t = 3 min = 180 s
Find: v and Δx
v = at + v₀
v = (0.5 m/s²) (180 s) + 0 m/s
v = 90 m/s
Δx = v₀ t + ½ at²
Δx = (0 m/s) (180 s) + ½ (0.5 m/s²) (180 s)²
Δx = 8100 m
A 7.12 μC charge is moving at the speed of light in a magnetic field of 4.02 mT. What is the force on the charge?
Answer:
858.7 N
Explanation:
The magnetic force on the charge F = Bqv where B = magnetic field strength = 4.02 mT = 4.02 × 10⁻³ T, q = charge = 7.12 μC = 7.12 × 10⁻⁶ C and v = c = speed of light = 3 × 10⁸ m/s
F = Bqc
= 4.02 × 10⁻³ T × 7.12 × 10⁻⁶ C × 3 × 10⁸ m/s
= 858.7 N
Dynamo converts the
a》mechanical energy into electrical energy
b》chemical energy into electrical energy
c》heat energy into electrical energy
d》none of the above
Answer:
[tex] \gamma \: dynamo \: converts \: the \: mechanical \: energy \: into \: electrical \: energy \: .[/tex]
Explanation:
Hope it helps you :)))
Answer:
.
Explanation:
An atom of xenon has a mass number of 127 amu. How many neutrons
does it contain? *
Answer:
73 neutrons.
Explanation:
Data obtained from the question:
Mass number of Xenon = 127.
Neutron number =...?
We can obtain the number of neutron present as follow:
Atomic number of Xenon = 54
Recall:
Atomic number = proton number = 54
Mass number = proton + neutron
127 = 54 + Neutron
Neutron = 127 – 54
Neutron = 73.
Therefore, 73 neutrons are present in the Xenon atom.
Compare and contrast speed, velocity, and acceleration. Why do their differences matter?
Answer:
Speed is a scalar quantity, that is, it is a number and indicates how fast (or slow) one travels at any given time.
Velocity is a vector quantity, this means that it has magnitude and direction, that is, how fast an object travels and its where its going (speed + the direction in which the object moves).
Acceleration is the ratio of the velocity change over the time interval in which this velocity change occurred. Acceleration as well as velocity is a vector quantity so it is made up of magnitude and direction.
The differences between these three quantities are important for the description of the movement. In the case of speed and velocity, its difference lies in the fact that velocity indicates the direction in which the movement is taking place (and speed is only a number), which in many physical phenomena the direction of movement is an important property. And the difference between acceleration and velocity is that acceleration instead of a velocity indicates a change in velocity (either in magnitude, direction or both), which tells us how fast a velocity will increase or decrease over time.
