Physics 101 Exam 1

3. You are lowering a load into a well. The load is attached to a rope and it moves downward with constant velocity. The tension in the rope is

b) Equal to the weight. *

15. You measure the weight of the same object (mass = 20 kg) on Earth (g = 10m/s2), on some moon (g = 1.0 m/s2) and on some weird planet where g = 100m/s2. What are your results.

d) None of the above. *

23. You are building an airplane using some leftover materials that you found in a junkyard. Which of the following materials would be best to use.

e) Only a) and b) *

21. My car has a mass of 100 kg. It travels on a road with coefficient of friction = 0.3. What is the force of friction acting on the car.

a) 300 N *

17. A cannon shoots a shell up with an initial vertical velocity component of 10m/s and an initial horizontal component of 30m/s. Neglecting air resistance and the curvature of the Earth, how far away from the cannon will the shell hit?

a) 60m. *

2. A load is being lifted with constant acceleration. The force pulling up the load is

a) Larger than the weight. *

8. A negative distance implies that an on object is

a) One the negative side of the origin. *

18. Assume that a cart of mass m is being pushed with a constant force of known magnitude. If the mass of the cart is halved and the force is not changed, the cart's acceleration will be

a) double

4. A car is moving on a highway with a speed of 60 m/s. 5 minutes later the car is moving at 60 m/s in the same direction. The car acceleration is

b) 0 *

13. A force of magnitude F = 10 N is applied to two different carts. One cart has a mass m = 10 kg, and the second cart has a mass m = 20 kg. What is the acceleration of each of the carts?

b) 1 m/s2, 0.5 m/s2 *

1. If you watch some old movies of astronauts walking on the Moon, you will notice that these folks were able to move around without difficulties even though they were wearing massive spacesuites. Why?

b) Because gravitation on the Moon is about 6 times lower than on earth. *

7. Why are some scientific statements often called laws?

b) Because they have been around for a long time and could not be proven wrong.*

10. Assume the x-axis to be an East-West line with the positive direction pointing East. A car is moving East with a speed of 30 m/s. The driver realizes that he forgot something at home. She stops the car, and turns around, moving West with a speed of 30 m/s. Under these assumptions, what is the velocity before and after turning around?

b) Positive before, negative after turning around. *

11. Galileo's approach to finding the laws of falling objects was to

b) Test the predictions of the established theory. *

6. A few weeks ago, a scientific module landed on a comet. One of the major technical hurdles was

b) To make the landing module stick to the comet because of the low gravitation. *

5. An athlete is lifting a load of 100 lb using a muscle which usually needs to apply 5 lb of force to lift a 1 lb of load. How much force is that muscle applying to lift the 100 lb load.

c) 500 lb *

12. A cannon shoots a shell straight up with an initial upward velocity of 300 m/s. Neglecting friction, how long will it take before the projectile lands back on the ground?

c) 60 s *

20. When we swim, we move arms and legs so that we push water

c) Opposite to the direction of motion. *

14. You are pushing a crate rightwards. The crate has a mass of 50 kg, and your force is 50 N. The surface is rough and the frictional force has a magnitude of 25 N. Where is the frictional force pointing? What is the magnitude of the acceleration?

c) Rightwards, 0.5 m/s2 *

16. A car goes from 0 m/s to 10 m/s in 1 second, moving along the negative x-axis. What is its acceleration.

d) -10 m/s2. *

22. A car goes from 0 m/s to 10 m/s in 1 second, moving along the negative x-axis. What is its acceleration.

d) -10 m/s2. *

19. Assume to move an object with a weight of 100 N to a planet with an acceleration of gravity which is 100 times higher than Earth's. The weight of the object on the new planet will be

d) 10,000 N. *

When a group of students enters a lecture room, does the floor change shape?

b) Yes it raises a bit

9. The position of a boat moving on a calm sea is an example of

c) A two dimensional system *