Question

A particle moves along straight line on y axis .The distance of the particle from O varies with time and is given by: y=20t-t^2.the distance travelled by the particle before it momentarily comes to rest is1. 200m2. 100m3. 50m4. 150m

Answer 1

The velocity of particle =

dy/dt =20-2t

the particle comes to rest when its velocity become 0.

so 20-2t=0
=> t=10
so at t=10 particle is at rest.

so distance travelled in t=10

y=20(10)-10^2
y=100