Question

Joaquin is at rest at the top of a hill on a skateboard. Four seconds later, he reaches the bottom of the hill at a final velocity of 20 m/s. What was his acceleration?

Answer 1

Explanation:

Given: Initial Velocity=0

Final Velocity= 20 m/s

Time= 4 s

Accleration: Unknowns

Use kinematic equation

$v _{f} = v _{i} + at$

$20 = 0 + at$

$\frac{20m}{s} = a(4s)$

$a = \frac{5m}{ {s}^{2} }$

so a = 5 m/s^2