Question

A cyclist is travelling at 15m/s. She applies brakes so that she does not collide with a wall 18m away. What deceleration must she have?​

Answer 1

Answer:

Given:

Initial velocity (u) = 15m/s

Final velocity (v) = 0m/s (it stops)

Distance (s) = 18m

Explanation:

According to 3rd equation of motion,

$2as = v^{2} - u^{2} \\ 18a = 0^{2} - 15^{2} \\18a = 0 - 225\\a = \frac{-225}{18} \\a = -12.5m/s^{2}$

⇒ Deceleration will be 12.5m/s