Physics

Problem

A ball is thrown straight downward from the top of a

45\,\text{m}

high school hostel with an initial speed of

5\,\text{m\,s}^{-1}

. a. (a) Taking the downward direction as positive, list the numerical values (with units and signs) of

u

s

and

g

that are relevant to the motion until the ball reaches the ground. b. (b) Choose an appropriate kinematic equation connecting

s

u

g

and

t

, and rearrange it algebraically to make

t

the subject. c. (c) Calculate the time taken by the ball to reach the ground, correct to two significant figures.