The height (in metres) of a ball thrown vertically upward is

MATHEMATICS · Multi-part · A Level · Mathematics · Kinematics · Kinematics

Problem

h(t)=20t-5t^{2}

, where

t

is the time in seconds after the ball is released. (i) Calculate the average velocity of the ball between

t=1\text{ s}

and

t=3\text{ s}

. (ii) Find the instantaneous velocity at

t=1\text{ s}

. (iii) State whether the ball is speeding up or slowing down at

t=1\text{ s}

, giving a brief reason based on your answers to parts (i) and (ii).