Mechanics | Relativity Answers

the potential energy of a particle of mass 1kg moving along x axis given by U(x)=[(X)sq/2 -x]joule .if total mechanical energy of particle is 2joule,find its maximum speed?

The momentum of a particle is p. The kinetic energy of the particle is doubled.
The momentum is now squre root of 2 p.. kindly explain how to get this

how is it possible for a car to travel a certain distance and have a zero displacement

a reservoir of volume 5 liters contains oxygen at N.T.P what is the mass of oxygen which should be pumped to the reservoir to raise the pressure to 4000,000 pascal without changing the temperature, given that the molecular weight of oxygen is 32

a rocket is launched with velocity 10km/s.if radius of earth is R ,what will be the maximum height attained by it ?

5. Before a sky diver opens his parachute, he may be falling at a velocity higher than the terminal velocity he will have after the parachute opens.

a) Describe what happens to his velocity as he opens the parachute. (2 marks)

b) Describe his velocity from after his parachute has been open for a time until he is about
to land. (2 marks)

6. From the top of a tall building, you drop two tennis balls, one ball is filled with air and the
other ball is filled with lead. Both experience air resistance as they fall.


a. Which ball reaches terminal velocity first? ( 1 mark)



b. Do both balls hit the ground at the same time? Explain.(2marks)

7. A book weighing - 14.55 N rests on an inclined plane at 36o from the horizontal.

a. Make a drawing of this situation. Draw and label the various force vectors(1 mark)

b. Find the components of the weight parallel and perpendicular to the plane.(4 marks)

1. What is the weight of a 2.88 kg snake? (1 marks)


2. A girl drops a rock straight down from a bridge. Assume negligible air resistance. How fast is it going 4.0 s later?
(2 marks)

3. A rock with a mass of 22.45 kg is falling from a tall tower.
a. What is the Net Force if the rock is in free fall? (1 mark)


b. What is the Net Force if the rock experiences an air resistance of 16.44 N (1 mark)


c. What is the Net Force when the rock reaches its terminal velocity of – 15m/s? (1 mark)


4. A 75.0 kg person stands on a scale in an elevator.

a. . What does the apparent weight (scale read) when the elevator is at rest? (2 marks)


b. . What does the apparent weight (scale read) when the elevator is climbing at a constant speed of + 3.00 m/s? (2 marks)


c. . What does the apparent weight (scale read) when the elevator accelerates upwards at + 1.46 m/s2? (2 marks)



d. . What does the apparent weight (scale read) when the elevator accelerates downwards at - 1.46 m/s2? (2 marks)

1) a force of 5 newton acts on a body for 0.2 sec. the change in momentum of the body is what?
2) if a force of 1 newton acts on a mass of 500 gram. acceleration will be what?

a student walks 180 m in 150seconds. the student stops for 40 seconds and then walks 210m farther in 2 minutes. what is the average speed of the entire walk?

A 60 kilogram student climbs a ladder a vertical distance of 4.0 meters in 8.0 seconds. Approximately how much total work is done against gravity by the student during the climb?