Study Guide for Physics MidTerm Test
Topics covered in the test
Linear Motion – speed, velocity, average speed, acceleration.
Free Fall – How fast, How far
Projectile Motion – horizontal and vertical motion
Newton’s Laws
Work and Energy
Power
Momentum and Impulse
Circular Motion
Center of Gravity
Torque
Angular Momentum and conservation of angular momentum
Practice Questions
1. Which has greater linear speed, a horse near the outside rail of a merry-go-round or a horse near the inside rail?
2. If you whirl a tin can on the end of a string and the string suddenly breaks, which direction the can will fly?
3. If you lift one load up two stories, how much work do you do compared to lifting one load up only one story?
4. An arrow in a bow has 70 J of potential energy. Assuming no loss of energy to heat, how much kinetic energy will it have after it has been shot?
5.As a pendulum swings back and forth, what forms of mechanical energy does it have? Can these form exchange into each other?
6. A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel, and 6 meters again during the third second. What is its acceleration?
7. Suppose an object is in free fall. How far does each second the object falls?
8. A 15-N force and a 45-N force act on an object in opposite directions. What is the net force on the object?
9. A girl whose weight is 500 N hangs from the middle of a bar supported by two vertical strands of rope. What is the tension in each strand?
10. The momentum of an object is defined as the object's ______.
11. In order to increase the final momentum of a golf ball, we could ______.
12. Friction is a force that always acts in the direction ______.
13. Will the law of inertia applies to objects at rest? How about moving objects?
14. When a woman stands with two feet on a scale, the scale reads 280 N. When she lifts one foot, the scale reads ______?
15. A book weighs 4 N. When held at rest in your hands, what much is the net force on the book?
16. Forces always occur ______.(by themselves, in pairs, in triplets)
17. The horizontal component of a projectile's velocity is independent of ______.
18. If you try to touch your toes while standing flat against a wall, you probably will fall over. The reason this happens is that
a. / your center of gravity is not located directly above your support area.b. / your center of gravity is outside your support area.
c. / both A and B
19. Suppose you try loosening a nut with a wrench, and the nut doesn't give at all. You increase your chance of success if you _____.
20. People in the future may well live inside a rotating space structure that is more than 2 km in diameter. Inside the structure, people on the inside of the outer edge will experience 1g while people halfway to the axis will experience ______g.
21. Which has more rotational inertia, a girl running with her legs bent or the same girl running with her legs straight?
True/False
Indicate whether the statement is true or false.
____ 22.A quantity that has both magnitude and direction is called a scalar quantity.
____ 23.A force can be simply defined as a push or a pull.
____ 24.The SI unit of mass is the newton.
____ 25.Average speed is defined as the time it takes for a trip divided by the distance.
____ 26.When a car rounds a corner at a constant speed, its acceleration is zero.
____ 27.A pulley system can change only direction; it can't multiply forces as well.
____ 28.It is possible for an object in free fall to have zero acceleration.
____ 29.Torque is the product of a force exerted on an object times the lever arm.
____ 30.It is possible to rotate a very large cylindrical space habitat around its central axis at just the right speed so people living inside the cylinder will experience a force that feels like gravity.
Essay
31.Discuss the difference between linear speed and rotational speed. Where does a ladybug sitting on a rotating record have the greatest linear speed? The greatest rotational speed? What kind of speed would she have at the center?
32.In terms of momentum change, explain why it is best to "give" when catching a baseball. Provide other examples of situations in which you want to lengthen the impact time in a collision.
33.Apply Newton's third law to a falling boulder, identifying the action and reaction forces. If a force is exerted on Earth, why doesn't it move? Explain.
Problem
34.A 45-kg girl runs up the staircase to a floor 15 m higher in 24 seconds. What is her power output?
35.You push with 36 N on a 20-kg chest, and there is a 14-N force of friction. How fast will the chest accelerate?
36.A ball is thrown horizontally from the top of a tall cliff. Neglecting air drag, what vertical distance has the ball fallen 4.0 seconds later?