Question

How much work must be done in the car to slow it from 100km/h to 50km/h

Answer 1

Answer:

$-96.465m$ joule

Explanation:

Let m = mass of the car and v1 = initial velocity and v2 = final velocity

Given.

Initial velocity = 100 km/h

final velocity = 50 km/h

What is work done in the car to slow it from 100km/h to 50km/h?

$v1=100km/h=27.78m/s$

$v2=50km/h=13.89m/s$

The work done in the car to slow it from v1 to v2.

w=Δk

$w=k2-k1$

$w= \frac{1}{2}m(v2)^{2}- \frac{1}{2}m(v1)^{2}$

$w=\frac{1}{2} m(v2-v1)^{2}$

$w=\frac{1}{2}\times m(13.89 -27.78)^{2}$

$w=\frac{1}{2}\times m(-13.89)^{2}$

$w=\frac{1}{2}\times m\times (-192.93)$

$w=-96.465m$ joule.

Therefore, the work done is $-96.465m$ joule