A ball is projected vertically upward from ground level with an initial velocity of

PHYSICS · Multi-part · CBSE · Physics · Motion in a Straight Line · Motion in a Straight Line

Problem

24\,\text{m/s}

. Its height above the ground after

t

seconds is modelled by

s(t)=24t-4.9t^{2}\quad \bigl(0\le t\le T\bigr),

where

T

is the time when the ball returns to the ground. (a) Derive the expression for the ball’s instantaneous velocity

v(t)

. (b) Determine the time at which the ball attains its greatest height. (c) Calculate that maximum height. (d) Find the velocity of the ball

2

seconds after it is projected and interpret the sign of your answer.