# Finding acceleration of a car when it is braking

• Amelina Yoo
In summary, the conversation discusses a 1200kg car moving at 20 metres per second that stops in a distance of 50m when the brakes are applied. The first part of the conversation asks for the acceleration of the car when it is braking, and the second part asks for the force applied by the car's braking system. The attempt at a solution uses the acceleration formula and the time formula to find the acceleration, but struggles to understand how to find the acceleration when braking. The expert summarizer notes that braking to a stop is the reverse of accelerating from a standing start and suggests using the SUVAT equation to relate acceleration, distance, and initial and final velocities.

## Homework Statement

A 1200kg car moving at 20 metres per second stops in a distance of 50m when the brakes are applied.
a) What is the acceleration of the car when it is braking?
b) Find the force applied by the car's braking system.

## Homework Equations

For a) I used the acceleration formula: a=(velocity - initial velocity)/t
Time formula from rearranging: t=s/v

## The Attempt at a Solution

a)
t=s/v
t=50/20=2.5s

velocity=50/2.5=20 metres per second

a=(20-0)/2.5 = 8ms(^-2)[/B]
I do not know how to find the acceleration when BRAKING, and the answer claims that it is 4ms(^-2.)

As for b, I believe that I am unable to attempt it seeing as I am unable to find the acceleration.

Please explain how to do it! I have read through the chapter of my textbook, and am unable to understand. thank you very much!

Last edited:
Amelina Yoo said:

## Homework Statement

A 1200kg car moving at 20 metres per second stops in a distance of 50m when the brakes are applied.
a) What is the acceleration of the car when it is braking?
b) Find the force applied by the car's braking system.

## Homework Equations

For a) I used the acceleration formula: a=(velocity - initial velocity)/t
Time formula from rearranging: t=s/v

## The Attempt at a Solution

a)
t=s/v
t=50/20=2n5s

velocity=50/2.5=20 metres per second

a=(20-0)/2.5 = 8ms(^-2)[/B]
I do not know how to find the acceleration when BRAKING, and the answer claims that it is 4ms(^-2.)

As for b, I believe that I am unable to attempt it seeing as I am unable to find the acceleration.

Please explain how to do it! I have read through the chapter of my textbook, and am unable to understand. thank you very much!

Braking to a stop is just the reverse of accelerating to speed from a standing start.

Your equation t = s/v works only for constant speed. I have no idea what "2n5s" means.

There is a SUVAT equation which relates acceleration, distance, and initial and final velocities which would be rather useful here.

## What is acceleration?

Acceleration is the rate of change of an object's velocity over time. It is measured in units of distance per time squared, such as meters per second squared (m/s^2).

## Why is it important to find the acceleration of a car when it is braking?

Knowing the acceleration of a car when it is braking is important for understanding the car's performance and safety. It can also help determine how much force is needed to slow down or stop the car, and how long it will take to come to a complete stop.

## How can the acceleration of a car when it is braking be calculated?

The acceleration of a car when it is braking can be calculated using the equation a = (v2-v1)/t, where a is acceleration, v2 is the final velocity, v1 is the initial velocity, and t is the time it takes to change from v1 to v2.

## What factors can affect the acceleration of a car when it is braking?

The acceleration of a car when it is braking can be affected by factors such as the weight and mass of the car, the condition of the brakes and tires, the road surface, and the speed at which the car is traveling.

## How can the acceleration of a car when it is braking be measured?

The acceleration of a car when it is braking can be measured using various tools such as a speedometer, accelerometer, or a data logger. These tools can record the car's velocity and time, which can then be used to calculate the acceleration using the equation mentioned in the previous answer.