1. Chapter 8,9,10 – Review

2. An object at rest begins to rotate with a constant angular acceleration. If this object rotates through an angle  in the time t, through what angle did it rotate in the time ½t? 60 0 0 5 1.½  2.¼  3.¾  4.2  5.4 

3. You are using a wrench to loosen a rusty nut. Which arrangement will be the most effective in loosening the nut? 60 0 0 5 1 3 4 2 1.1 2.2 3.3 4.4 5.All are the same

4. A 1kg ball is hung at the end of a rod 1m long. If the system balances at a point on the rod 0.25m from the end holding the mass, what is the mass of the rod ? 60 0 0 5 1kg 1m 1.¼ kg 2.½ kg 3.1 kg 4.2 kg 5.4 kg

5. Water flows through a 1 cm diameter pipe connected to a ½ cm diameter pipe. Compared to the speed of the water in the 1 cm pipe, the speed in the ½ cm pipe is: 60 0 0 5 v1v1 v2v2 1.one quarter 2.one half 3.The same 4.double 5.four times

6. A helium balloon in an air-filled glass jar floats to the top. If the air is replaced with helium, what will happen to the helium balloon? 60 0 0 5 1.It still floats at the top because it has positive bouyancy 2.It stays in the middle because it has neutral bouyancy 3.It sinks to the bottom because it has negative bouyancy 4.The balloon shrinks in size due to the surrounding helium. 5.The balloon grows in size due to the lack of surrounding air.

7. Answers 1.2 –  =  o +  o t + ½  t2 2.2 – t = r F sinq, so long lever arm and at a right angle makes the biggest torque 3.3 – 1 kg, the mass of the rod acts at its center of mass which happens to be the same distance from the pivot as the 1-kg hanging mass. 4.5 – four times. A1 v1=A2 v2 and A is proportional to the diameter squared 5.3 – it sinks due to negative bouyancy, now the inside and outside of the balloon are both helium so have the same density, but the balloon’s rubber has a higher density so the overall density of the balloon is slightly higher than the surrounding helium