(c) The ball leaves the tennis player's racket at a speed of 50 m/s and travels a distance of 20 m before bouncing.
(i) Calculate how long it takes the ball to travel this distance.
(1 mark)

t=0.417s

Explanation:

After the ball hits the racket it is in freefall(assume air resistance as negligible)

so a=-g

use

x-x0=v0t+1/2at^2

Plug in givens

20=50t-4.9t^2

Solve quadratic equation using quadratic formula

t= 0.417 seconds, (the other answer is extraneous because it is too big because in 1 second, the ball travels 50 meters)

e

explanation:

there is no change in the electric potential energy as it is in rest on both conditions.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it