# A 1500 kg car accelerates from 50 m/s to 36 km/h in 8.0 s.what is the braking force of the car? How far does it go before coming to a stop?

Please help! I am teaching myself and I am still having problems.

A 1500 kg car accelerates from 50 m/s to 36 km/h in 8.0 s.what is the braking force of the car? How far does it go before coming to a stop?

### 3 Answers

- electron1Lv 75 months ago
To calculate the braking force, we need to calculate the acceleration. The following equation can be used.

vf = vi + a * t

To solve this problem, the unit of velocity should be converted from km/h to m/s. One kilometer is 1,000 meters. One hour is 3,600 seconds,

One km/h = 1,000/3600

To reduce this fraction to simplest terms, divide the numerator and denominator by 200.

One km/h = 5/18 m/s

v = 5/18 * 36 = 10 m/s

10 = 50 + a * 8

a = -5 m/s^2

Now we can calculate the braking force.

F = m *a = 1,500 * -5 = -7,500 N

Let’s use the following equation to calculate the distance the car moves as its velocity decreases from 50 m/s to 0 m/s.

vf^2 = vi^2 + a * a * d

0 = 50^2 + 2 * -5 * d

d = 2,500 ÷ 10 = 250 meters

I hope this helps you to understand how to solve this type of problem.

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- oubaasLv 75 months ago
Vi = 50 m/sec

Vf = 36/3.6 = 10 m/sec

acceleration a = (Vf-Vi)/T = (10-50)/8 = -5.0 m/sec^2

braking force BF = m*a = 1500/1000*-5 = -7.50 kN

distance to stop d = -(Vi^2)/2a = -(50^2)/(2*-5) = -2500/-10 = 250 m

distance at slow down d' = (Vf^2-Vi^2)/2a = (10^2-(50^2))/-10 = 240 m

- ?5 months agoReport
Vf is = 50m/s

Vi is 36km/h ?

can you explain in detail in this problem? don't follow - Log in to reply to the answers

- 5 months ago
Stop asking me hard questions I never was good at maths

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