Question

A car starts from rest and attains a velocity of 10m/s in 40s.The driver applies brakes and slows down the car to 5m/s in 10s. Find the acceleration of the car in both the cases.

Answer 1

Answer:

A=0.5m/s

Explanation:

In first case

Initial velocity of a car is 0 m/s

Final velocity of car is 10 m/s time=40sec

Then, acceleration =v-u\t

a=10-0\40=0.25m/s²

Now in second case,

Initial velocity =5m/s

Final velocity =0m/s

Time=10sec

Then, a/q the driver applies breakers to slow down so,

a=5-0\10=0.5m/s²

Answer 2

Your Answer:

Given:-

• A car starts from rest and attains a velocity of 10m/s in 40s
• The driver applies brakes and slows down the car to 5m/s in 10s

To Find:-

• Acceleration.

Solution:-

Acceleration is the rate of change of velocity

$\tt \blue{a=\dfrac{v-u}{t}}$

In the case 1

$\tt u = 0 \\\\ \tt v = 10 m/s \\\\ \tt t = 40 s\\\\ \tt a = \dfrac{v-u}{t} \\\\ \tt= \dfrac{10 - 0}{40} \\\\ \tt= 0.25 ms^{-2}$

In case 2

$\tt u = 10 \\\\ \tt v = 5 ms^{-1} \\\\ \tt t = 10 s\\\\ \tt a = \dfrac{5 - 10}{10} \\\\ \tt= \dfrac{-5}{10} \\\\ \tt= -0.5 ms^{-2}$