Question

Find the initial velocity of a car which stops in 10sec, after applying brakes at the rate of 2m/s²

Answer 1

Answer:

$20\ m/s$

Explanation:

Since we are given time, acceleration, and final velocity, we can use the following formula to find the initial velocity:

$v_f = v_i + at$

Our given values:

$v_f = 0\\a = -2\\t = 10$

Acceleration is negative because the car is slowing down.

Add the values to the formula, and solve for $v_i$:

$v_f = v_i + at\\0 = v_i + (-2)(10)\\0 = v_i -20\\20 = v_i$