REVIEW FOR DIAGNOSTIC EXAM 1Q AY 2012-2013

SUBJECT: PHY11

7. The 2 kg head of an axle strikes a tree horizontally at 40 m/s. The blade penetrates 0.040 m into the tree. What is the average force exerted by the blade on this rate? a. 2.0 x 101 N b. 2.0 x 103 N c. 2.0 x 104 N d. 4.0 x 104 N

Work, Energy & Power

30. How much work must be done to stop a 1800-kg vehicle traveling at 30 m/s? a. 1.80 x 104 J b. 5.40 x 104 J c. 5.30 x 105 J d. 8.10 x 105 J

Work, Energy & Power

18. An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice the height in half the time, the power output is a. four times as much PE b. twice as much PE c. three times as much PE d. the same as before

Work, Energy & Power

4. Calculate the minimum power a cyclist who can increase his kinetic energy from an initial value of 480 J to a final value of 2,430 J by travelling 26 m in 4.0 s. a. 77.5 W b. 367. 5 W c. 727.5 W d. 487. 5 W

Work, Energy & Power

2. A net force of 20 N acts for 1.5 s on a 4 kg object initially at rest. What is the final kinetic energy of the object? a. 32 J b. 232 J c. 442 J d. 112 J

Impulse & Momentum

5. Which of the following best represents the momentum of a small car traveling at a city speed limit? a. 1,000 kg m/s2 b. 10,000 kg m/s c. 100,000 kg m2

d. 1,000,000 N m/s

Impulse & Momentum

20. A 0.5-kg ball is thrown horizontally along a vertical wall at 35.0 m/s. The ball hits the wall and rebounds horizontally at 25.0 m/s. If the ball is in contact with the wall for 0.015 s, the average horizontal force that the wall exerts on the ball during impact is a. 1.50 N b. 2.00 N c. 2.50 kN d. 3.00 kN

Impulse & Momentum

21. At t = 0, a wheel rotating about a fixed axis at a constant angular acceleration has an angular velocity of 2.0 rad/s. Two seconds later it has turned through 5.0 complete revolutions. What is the angular acceleration of this wheel? a. 14 rad/s2 b. 17 rad/s2

c. 20 rad/s2 d. 23 rad/s2

Rotational Motion

27. A spinning ice skater stretches out her arms. Her moment of inertia _______ and her angular speed _______. a. increases - increases b. increases – decreases c. decreases-decreases d. decreases-increases

Rotational Motion

26. A hollow cylinder of mass M and radius R rolls down an inclined plane. A block of mass M slides down an identical inclined plane. If both objects are released at the same time, a. the cylinder will reach the bottom first. b. both the block and the cylinder will reach the bottom at the same time. c. the block will reach the bottom first. d. the cylinder will reach the bottom with the greater kinetic energy.

Rotational Motion

28. A string is wrapped around a pulley of radius 0.10 m and moment of inertia 0.15 kg-m2. The string is pulled with a force of 12 N. What is the magnitude of the resulting angular acceleration of the pulley? a. 18 rad/s2 b. 80 rad/s2

c. 8.0 rad/s2 d. 0.13 rad/s2

Rotational Motion

9. What is the unit of torque?

a. N/m

b. N/s

c. N - m

d. N s

Torque

29. A 35 kg uniform plank is balanced at one end by a 55 kg student as shown. What is the overall length of this plank? a. 2.6 m b. 3.3 m c. 5.4 m d. 6.7 m

Torque

22. A cable stretches by the amount x under a certain load. If it is replaced by a cable of the same material but half as long and half the diameter, the same load will stretch it by a. x/4 b. x c. x/2 d. 2x

Elasticity

23. The stress on the wire supporting the load does not depend on a. the wire’s length b. the wire’s diameter c. the mass of the load d. the acceleration due to gravity

Elasticity

24. A 20-m long steel wire (1 cm2 cross-section, Y = 2 x 1011 N/m2), is subjected to a load of 25,000 N. How much will the wire stretch under the load? a. 0.25 cm b. 2.50 cm c. 12.50 cm d. 25.00 cm

Elasticity

25. When a force of 20 N is applied to a spring, it elongates 0.20 m. Determine the period of oscillation of a 4-kg object suspended from this spring. a. 0.80 sec b. 1.00 sec c. 1.30 sec d. 3.10 sec

Simple Harmonic Motion

10. The height of the mercury column in a barometer is 760 mm of Hg. Find the atmospheric pressure in Pascal. a. 1.013 x 105 Pa b. 2.013 x 105 Pa c. 3.012 x 105 Pa d. 3.021 x 105 Pa

Hydrostatics

14. Fluids at rest at the bottom of the container is a. under less pressure than the fluid at the top. b. under same pressure than the fluid at the top. c. under more pressure than the fluid at the top. d. any of the above, depending on the circumstances.

Hydrostatics

13. A hydraulic lift has a large piston 30 cm in diameter and a small piston of 2 cm in diameter. What force is needed on the small piston to lift a load of 1,500 kg? a. 55 N b. 65 N c. 75 N d. 85 N

Hydrostatics

12. A block of wood floats in water with 5 cm projecting above the water surface. When placed in glycerine of specific gravity 1.35, the block projects 7.5 cm above the liquid. Determine its specific gravity. a. 0.568 b. 0.765 c. 0.658 d. 0.850

Hydrostatics

11. How much water in m3 will escape per minute from an open-top tank through an opening 3 cm in diameter that is 5 m below the water level in the tank? a. 0.52 m3 b. 0.42 m3 c. 0.32 m3 d. 0.22 m3

Hydrodynamics