Question

A driver of a car traveling at 15.0 m/s applies the brakes, causing a uniform acceleration of -2.0 m/s/s. How long does it take the car to come to a stop? Use the GUESS method. Please help me asap.

Answer 1

For this, we will use the formula:

a = [V₀⁻V₁]÷t

Where:

a - Acceleration
V₀ - Final Velocity
V₁ - Initial Velocity
t - Time

Given:
a = -2.0 m/s²
V₁ = 15.0 m/s
V₀ = 0 m/s ; because the car stopped

Find:
t = ?

Solution:

a = [V₀⁻V₁]÷t

First, we should derive the formula to the element that we are looking for (which is time).

t = [V₀⁻V₁]÷a
t = [0 m/s - 15.0 m/s]÷(-2.0 m/s²) ; substituting the numbers
t = -15.0 m/s ÷ -2.0m/s²
t = 7.5 seconds ; cancelling the removable units thus resulting only to the time unit s(seconds)

It took the car 7.5 seconds to stop