Question

If a rock is thrown upward on the planet mars with a velocity of 17 m/s, its height (in meters) after t seconds is given by h = 17t − 1.86t2. (a) find the velocity of the rock after one second.

Answer 1

height of the object is given in terms of time t

$h = 17t - 1.86 t^2$

now rate of change in height is velocity

so we can say

$v = \frac{dh}{dt}$

$v = 17 - 3.72 t$

now at t  = 1 s

$v = 17 - 3.72$

$v = 13.28 m/s$

so its speed will be 13.28 m/s