A body is projected up such that its position vector varies with time as `r = { 3thati + (4 t - 5t^2)hatj}` m. Here, t is in seconds. Find the time and x-coordinate of particle when its y-coordinate is zero.

Answer

A, B, C, D

Explanation

y-coordinate of particle is zero
when,
`4t - 5t^2 = 0`
`:. t = 0 and 0.8 s`
`x = 3t`
at t = 0, x = 0
and at t=0.8 s, x = 2.4 m.