Physics problems

Kinetic Energy

A 1000 kg car is driving at a speed of 30 m/s. It starts to slow down at a rate of 2 m/s/s. What is its kinetic energy after 6 seconds of deceleration?

Force of Friction

A boulder with a mass of 80 kg is sitting at the top of a hill with an angle of 16 degrees above the horizontal. It starts at rest and begins rolling down the hill. It takes 5 seconds for the boulder to roll 30 meters down the hill. What is the force of friction?

Tug of War (Angular Force)

Alan, Bob, and Claire are playing tug of war. Alan is pulling with a force of 75 N at 30 degrees, Bob is pulling with a force of 100 N at 135 degrees, and no one is winning. With what force, and in what direction, is Claire pulling?

Centripetal Force

A 3 kg ball is swinging from a rope 50 cm long with a centripetal force of 1,536 N. The rope is cut when the rope is parallel to the ground; as a result, the ball flies straight up in the air. How long does it take until the ball reaches its maximum point?