Question

A particle has initial A particle has initial velocity `10m//s`. It moves due to constant retarding force along the line of velocity which produces a retardation of `5 m//s^(2)`. Then
A. the maximum displacement in the direction of initial velocity is `10m`
B. the distance travelled in first `3` secondary is `7.5m`
C. the distance travelled in first `3` seconds is `12.5m`
D. the distance travelled in first `3` secondary is `17.5m`

Answer 1

Correct Answer - A::C
Particle comes to instantanous rest at
`v = x +at`
`0 = 10 - 5t`
`t = 2sec`
(A) `x_("max") = ut +(1)/(2) at^(2)`
`rArr x_("max") = 10 xx 2 +(1)/(2) xx (-5) xx (2)^(2)`
`x_("max") = 20- 10 rArr x_("max") = 10m`
(B) Distance travelled = Sum of area convered by `v-t` graph on time axis
`=(1)/(2) xx 2xx 10+(1)/(2) xx 1xx 5 = 12.5m`