A student throws a set of keys vertically upward to his fraternity brother, who is in a window 4.20 m above. The brother's outstreched hand catches the keys 1.80 s later. (a) With what initial velocity were the keys thrown

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

A2k pendulum has a speed of 1 m/s at a height of 1/2 meter

The friction of the water on a boat produces an acceleration of -10. m/s2. if the boat is traveling at 30. m/s and the motor is shut off, how long it take the boat to slow down to 5.0 m/s?