EZ Phys test

1. A brick is dropped from a height of 3 meters.

a) How far does it drop in the first tenth of a second?

b) How much time does it take to reach the ground (from the time it was dropped)?

c) What speed did it have the instant before hitting the ground?

2. Add two vectors. One is in the x direction with a magnitude of 12, the other in the y direction with magnitude 16. Find the magnitude and direction of the resultant.

3. Add the same two vectors except that the 16 is in a direction 30 degrees to the left of the +y axis.

4. A frictionless 10 kg wagon is pulled on a horizontal surface with a 5 Newton horizontal force. Find the acceleration.

5. Repeat # 4 if the 5 N force is inclined 30 degrees above horizontal.

6. Repeat # 5 if there is a frictional force of magnitude 2 N also.

7. In problem 4, find the work done by the 5 N force as the wagon is pulled 20 m.

8. In problem 5, find the work done by the 5 N force as the wagon is pulled 20 m.

9. In problem 6, find the work done by each force as the wagon is pulled 20 m.

10. Discuss the energy transfers in problem 9.

11. A 2 kg ball is tied to a 3 m string. The string is tied to a tree branch. The ball is raised up to the tree branch height with the string horizontal (no slack), then released. Find its speed when it is at the low point of the arc (use energy).

12. In problem 11, find the tension in the string when the ball is at its low point.

13. A 20 kg child is in a wagon going 4 m/s when she jumps off the front. At the instant she leaves the wagon, she is traveling 5 m/s and the wagon now is going 2 m/s. Find the mass of the wagon. All velocities are horizontal and in the same direction.

14. A motor has inertia 0.10 kg m². It is turning at the rate of 1200 rpm or 126 rad/s when it is turned off. Then it slows down and stops in 5 seconds due to a constant frictional torque. Find the frictional torque.

Here are my main physics pages:
Mechanics
Fluids, heat, electricity and magnetism
Vibrations and waves
Quantum
alphabetical quickies: index

Comments, questions: fredrick.gram at tri-c.edu (remove spaces and replace at with @. This is my defense against spammer software that gets email addresses that are listed on the web).