Question

1.

(a) What is the angular speed (in rpm) with which the Earth spins on its axis?   

(b) What is the angular speed (in rpm) with which the Earth revolves around the Sun? 

2. 

(a) When rebuilding her car's engine, a physics major must exert 230 N the normal force in newtons between the piston and cylinder? force to insert a dry steel piston into a steel cylinder. 

(b) What is the magnitude of the force in newtons she would have to exert if the steel parts were oiled?

3. 

(a) What is the maximum frictional force (in N) in the knee joint of person who supports 83.0 kg of her mass on that knee? 

(b) During strenuous exercise it maximum force of friction (in N) under such conditions? (The frictional forces in joints are relatively small in all circumstances except when the joints deteriorate, such as from injury or arthritis. Increased frictional forces can cause further damage and pain.) 

Answer 1