An object is projected vertically upward from the top of a platform that is metres…

PHYSICS · Multi-part · CBSE · Physics · Gravitation · Gravitation

Problem

An object is projected vertically upward from the top of a platform that is

h

metres above the ground with an initial speed

u

. Neglect air resistance and take the acceleration due to gravity as

g

. (a) Derive an expression for the total time of flight

T

until the object strikes the ground in terms of

u,\,h

and

g

. (b) Show that your expression reduces to the well-known result for level ground when

h=0

. (c) Using the expression obtained in part (a), calculate the total time of flight for

u=18\,\text{m\,s}^{-1}

and

h=30\,\text{m}

, taking

g=9.8\,\text{m\,s}^{-2}