Study Guide Chapters 5, 6, 7 & 8

Tips:

• In the chapter summaries read the Useful Concepts and be familiarized with the terminology from the Important Terms list.
• Work out ALL the Practice Problems
• Start studying at least 1 week prior to the exam.
• Read the chapters thoroughly
• Take good and legible lecture notes
• Take breaks between studying time

Practice Problems

SHOW ALL WORK

1. A crane does 500 J of work to lift a box a vertical distance of 8.5m. Calculate the mass of the box.

A.) 6 kg

B.) 11 kg

C.)       17 kg

D.)       22 kg  

2. A centripetal force does no work because

A.) The motion is curved

B.) There is no acceleration

C.) The force is parallel to the motion

D.) The force is perpendicular to the motion

3. An engine is being used to raise a 96 kg crate vertically upward. If the power output of the engine is 1150 W, how long does it take the engine to lift the crate a vertical distance of 10.2 m? Friction is negligible.

4. A ball on a string is being whirled in a horizontal circle. If the speed is doubled what happens

to the tension in the string?

(a) It remains the same  (b) It doubles  (c) It quadruples (d) It decreases by a factor of two

5. A 95 kg skier starts from rest at point A on a ski slope, 15 m above the horizontal, skies down the hill through point B onto a rough horizontal plane. A constant frictional force of 55 N acts on the skies along the plane, which brings the skier to rest at point C. Assume the slope is frictionless.

a.) What is the speed of the skier at point B?

b.) How far does the skier travel from B to C?

A.) 5.55 x 10⁴ N

B.) 3.65 x 10⁶ N

C.) 4.41 x 10⁶ N

D.) 3.65 x 10⁵ N

6. In physics power is

 (a) the same as force  (b) another form of kinetic energy

 (c) has unit units of ft-lb

 (d) the rate at which work is done

 

7. Provide the units of the following quantities in SI.

   Frictional force, Energy, Work, Power, and centripetal acceleration.

8. How fast is she moving when she hits the water? A woman runs with a speed of 6m/s     off a platform that is 10m above the water. Ignore air resistance

9. Find the potential energy of an object ( mass = 35 kg) which is 25 km above the ground level.

10. Find the force between objects of masses m₁=5.0x10³ kg, m₂=3.0x10³ kg, separated by a distance r=3.0m. ( G = 6.67x10^-11 N.m / kg² )

11. A 10.0 kg object, initially at rest, explodes breaking into two pieces of mass 2.0 kg and 8.0 kg. The 2.0 kg piece has a speed ----------- the speed of the 8.0 kg piece.

(a) five times  (b) four times  (c) one-fourth as long as  d) one-fifth as large as.

12. In an inelastic collision only

(a) kinetic energy is conserved (b) momentum is conserved

(c) force is conserved (d) both a and b are conserved.

13. Calculate the distance from the sun to Saturn, given that Saturn's period of revolution about the sun is 29.46 years.

14. The Earth is 1.5x10 11 m from the sun and has period of 365 days. Determine the magnitude of its centripetal acceleration.

15. A spring with spring constant 10  N/m was compressed 5 cm, how much energy is stored in the spring?

16. A 70 kg person runs up a staircase 3.0 m high in 3.5 s. How much power does he develop in climbing the step?

17. A 50 kg ice skater is standing at rest on a frozen lake. The friction is neglected. If he throws a 2.o kg block of ice horizontally with a velocity of 12 m/s, what is his recoil velocity?

18. An 2 kg physics book flies through the sir with a momentum of 20 kg. M/s. What is its speed?

19. A croquet mallet delivers an impulse of 8.83 N.s to a 0.5 kg croquet ball intially at rest. What is the speed of the ball immediately after being stuck?

20. A 1500-kg automobile moving at 15 m/s strikes an automobile stopped at a traffic light from behind, hooking bumpers. The two cars continue to move together at 10 m/s. What was the mass of the struck car? A. 1500 kg, B. 1250 kg, C. 1000 kg D. 750 kg