Acceleration Physics Example 2

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Example 2

medium
A car traveling at 25 m/s25 \text{ m/s} brakes and comes to rest in 5 s5 \text{ s}. What is the deceleration, and how far does it travel while braking?

Solution

  1. 1
    First find the acceleration from the change in velocity: a=vf−vita = \frac{v_f - v_i}{t}.
  2. 2
    Deceleration: a=0−255=−5 m/s2a = \frac{0 - 25}{5} = -5 \text{ m/s}^2
  3. 3
    Distance: d=vit+12at2=25(5)+12(−5)(25)=125−62.5=62.5 md = v_i t + \frac{1}{2}at^2 = 25(5) + \frac{1}{2}(-5)(25) = 125 - 62.5 = 62.5 \text{ m}

Answer

a=−5 m/s2,d=62.5 ma = -5 \text{ m/s}^2, \quad d = 62.5 \text{ m}
Negative acceleration (deceleration) means the object is slowing down. The kinematic equations allow us to find displacement during non-uniform motion.

About Acceleration

The rate at which an object's velocity changes over time, measured in metres per second squared (m/s²).

Learn more about Acceleration →

More Acceleration Examples

Example 1 easy

A car accelerates from [formula] to [formula] in [formula]. What is the acceleration?

Example 3 medium

An object starts from rest and accelerates at [formula] for [formula]. What is the final velocity an

Example 4 medium

A cyclist accelerates uniformly from [formula] to [formula] over [formula]. (a) What is the accelera

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