A 1.2 kg rock is falling at a speed of 14 m/s when it is 9.2 m above the ground. Calculate its kinetic energy when it is 2.6 m above the ground.

The stopwatch used by a student to measure velocity of a pulse in a slinky was of least count 0.1 second. he stops the stopwatch when a pulse has made 3 journeys from one end to the other of the slinky. he finds the seconds hand to be at 52nd division. calculate the correct time noted by him.