- #1

Amber_

- 7

- 0

## Homework Statement

Here is the problem:

You are driving at the speed of 28.4 m/s

(63.5426 mph) when suddenly the car in

front of you (previously traveling at the same

speed) brakes. Considering an average human

reaction, you press your brakes 0.505 s later.

Assume that the brakes on both cars are fully

engaged and that the coeﬃcient of friction is

0.719 between both cars and the road.

The acceleration of gravity is 9.8 m/s 2

Calculate the acceleration of the car in front

of you when it brakes.

Answer in units of m/s 2

Note: this is the first part of a multipart question.

**2. The attempt at a solution**

I know exactly how I would do this problem, were the masses of the cars given. I honestly have no idea how you would get the acceleration due to friction without knowing the mass of the car. Is it possible that this is a mistake in the problem, or am I missing something?