Chapter 5

1. Determine the force of gravity on a 50 kg person and a 100 g bullet on the moon if the

gravitational field constant of the moon is 1.6 N/kg.

2. An elevator of mass 2000 kg is supported by a cable. Determine the tension in the cable if

a) the elevator is not moving..

b) the elevator moves up at a constant velocity of 1.5 m/s.

c) the elevator moves down at a constant velocity of 1.5 m/s.

d) the elevator accelerates up at 1.0 m/s².

e) the elevator accelerates down at 1.0 m/s².

3. Calculate the force of gravity on a 60.0 kg astronaut if she stands on

a) Mars (g = 3.27 N/kg)

b) Uranus, (g = 10.49 N/kg)

c) Pluto, (g = 0.31 N/kg)

4. A spider lowers itself on a strand that supplies a force of 5.6 X 10^-4 N. The mass of the spider

is 0.10 g. What is the acceleration of the spider?

5. A spring scale attached to the roof of an elevator supports a fish. Determine

a) the weight of the fish if the elevator accelerates at +1.2 m/s², and the scale reads 200 N.

b) the conditions in which the scale will read 150 N?

c) the scale reading if the cable which supports the elevator breaks.

6. Determine the acceleration of a 15 kg mass situated on a level table, if it is attached by a rope

that runs over a friction less pulley to a 40 kg block, which is free to fall to the floor beside the

table.

7. Given the diagrams below,

2) find the tension in the string(s).

3) determine the acceleration of the systems.

4) for a time of 1.2 s, calculate how far each mass moves if they start from rest.

8. It takes 2.2 s for a 10 kg box to come to rest. While coming to rest, the box slides 6.0 m.

What is the coefficient of kinetic friction between the box and the floor it slides on?

9. A 200 N force is applied at 30^o above horizontal, to drag a 50 kg crate across a floor. The

coefficient of friction between the floor and the crate is 0.30. Determine

a) the normal force on the crate.

b) the frictional force on the crate.

c) the crate's acceleration.

10. A beer can sliding with a speed of 2.0 m/s comes to rest. The coefficient of friction is 0.20.

How far does the can slide?

11. We find the gravitational field constant is 9.5 N/kg when 150 km above the Earth's surface.

Determine

a) the weight of a 60 kg astronaut at this altitude.

b) the velocity of a rock dropped from rest at this altitude after 10 s.

12. The following graph is for a 1.0 kg ball dropped in air.

a) Determine the ball's acceleration when velocity is 8.0 m/s.

b) Determine the fastest falling velocity for the ball.

c) What is the acceleration of the ball, just after being fired downwards at 22 m/s?

13. A 200 g pendulum has a length of 1.12 m.

a) Calculate the tension in the string when the pendulum is not moving.

b) If the pendulum moves at 1.2 m/s at the bottom of the swing, what is the tension in the

string?

14. A 2.5 kg ball is swung in a vertical circular path of radius 1.5 m. How fast will the ball be

moving at, if at the top of the circle, the tension in the rope is zero?

15. A pail of water with a mass of 3.0 kg is swung in a vertical circle with radius 1.3 m. If the

velocity is 6.0 m/s, calculate the maximum and minimum tension in the attached rope.

16. A pendulum of mass 1.0 kg makes an angle of 10^o with the vertical. If the pendulum is

attached to the roof of a car which is accelerating, what is the acceleration of the car?

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November 19, 2013