Q. An electric motor rotating a workshop grinding wheel at a rate of 107 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 1.70 rad/s2.
How long does it take for the grinding wheel to stop?
Q. Two 2.40 103-kg cars both traveling at 16.0 m/s undergo a head-on collision and stick together. Find the change in entropy of the surrounding air resulting from the collision if the air temperature is 21°C. Ignore the energy carried away from the collision by sound.