Tommy pushes a 40 kg crate along a rough surface with 90N of force. He observes that it is only accelerating a a rate of 200 km/s. What must the value of the force of friction be? (Assume the only two forces acting on the
object are friction and Derek)

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.