A box sliding down a hill going 3m/s accelerates at 2m/s2. How fast is going 4 seconds?

11 m/s

Explanation:

The motion of the box is a uniformly accelerated motion (=constant acceleration), therefore we can use the following suvat equation:

where:

v is the final velocity

u is the initial velocity

a is the acceleration

t is the time

For the box in this problem, we have:

u = 3 m/s is the initial velocity

is the acceleration

t = 4 s is the time interval

Solving for v, we find the velocity after 4 seconds: