Question

A rocket's acceleration is 6.0 m/s2. Assuming it starts at 0 m/s, how long will it take for the rocket to reach a velocity of 42 m/s?
250 s
0.14s
7.0 s
290 s

Answer 1

There are few equations that link acceleration and velocity.

One of them is derived from the definition of acceleration - is the rate of change of velocity in respect with time

a = v-u/t
at=v-u

a = acceleration
v=velocity at the end
u=velocity at the start
t=time

Now put everything you know and solve for time.

6t = 42 -0
6t = 42
t = 42 / 6
t = 7 second

It takes 7 seconds for the roccet to reach a velocity of 42 m/s

Hope it helps :).