Question

The brochure advertising a sports car states that the car can be moving at 100.0 km/h, and stop in 37.19 meters. What is its average acceleration during a stop from that velocity? Express your answer in m/s2. Consider the car's initial velocity to be a positive quantity.

Answer 1

The brochure advertising a sports car states that the car can be moving at 100.0 km/h, and stop in 37.19 meters. What is its average acceleration during a stop from that velocity? Express your answer in m/s². Consider the car's initial velocity to be a positive quantity.

Solution:

Let:

$$v = 100 \, \text{km/h} = 27.78 \, \text{m/s}$$ $$S = 37.19 \, \text{m}$$

a–?

$$v = at, \, S = \frac{1}{2} at^2 \Rightarrow t = \sqrt{\frac{2s}{a}}$$ $$v = \sqrt{2as}$$ $$a = \frac{v^2}{2s}$$ $$a = \frac{27.78^2}{2 \cdot 37.19} = 10.38 \, \text{m/s}^2$$

Answer: 10.38 m/s²