Question

If a hockey player starts from rest and accelerates at a rate of 2.1 m/s2, how long does it take him to skate 30 m?

Answer 1

You can use the following kinematic equation \[s = v_0 t + 1/2at^2\] notice the term \[v_0 t\] gets cancelled out as you are starting from rest (v_0 = 0).
So you're left with \[s = 1/2at^2\] s is the distance, a is the acceleration, solve for t.