Question

A car of mass 2000kg is moving at velocity 90km/h. The driver applied the brakes then,It came to rest after 50 sec.find the force applied by the brakes on it.

Answer 1

Explanation:

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Answer 2

Answer:

A car of mass 2000kg is moving at a velocity 90 km/h. The driver applied the brakes then, It came to rest after 50 sec. The force is applied by the brakes on it will be $-1000 \ N$.

Explanation:

We have Newton's second law of motion as,

$F = ma$     ...(1)    

Where m  is the mass of the object and 'a' is acceleration

Force (F) applied can be calculated by this law.

Acceleration can be obtained by calculating the rate of change of velocity with respect to time.

So,

$a = \frac{v-u}{t}$    ...(2)

Then first equation become,

$F =m( \frac{v-u}{t})$  ...(3)

where

u -  Initial velocity

v -  Final velocity

t  -  Time

From the question,

$u = 90\ km/h = 90\times \frac{5}{18} = 25\ m/s$

$v = 0$

$m = 2000\ kg$

$t = 50 \ s$

Substituting these values into equation (3),

$F =2000( \frac{0-25}{50}) =-1000\ N$