physics question

Question

An car is brought to rest in a distance of 484 m using a constant acceleration of -8.0 m/s². What was the velocity of the car when the acceleration first began?

Answer 1

Use the kinematic relationship:

v² - v₀² = 2ad ⇒

v₀ = √(v² - 2ad)

Plug in the values:

v = 0 (full stop)

a = -8.0 m/s²

d = 484 m

and get the initial speed v₀ in m/s. Be careful with the signs.