A ball leaves a point P at the top of a hill with a horizontal velocity of 15 m/s as shown. Calculate the magnitude of the velocity of the ball in m/s when it hits the ground at Q.

its c its is a mixture of gases

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.