Q. A 0.025kg golf ball moving at 23 m/s crashes through the window of a house in 2.0 10-4 s. After the crash, the ball continues in the equal direction with a speed of 10m/s. assume the force exerted on ball by the window was constant, what was magnitude of this force?
Q. A 5.7x10^2 kg hot-air balloon takes off from rest at the surface of the earth. The wind and lift forces take the balloon up, doing +9.7 x 10^4 J of work on the balloon in the procedure. At what height above the surface of the earth does the balloon have a speed of 7.50m/s?