Question

solve this question!!!!!!!!!!​

Answer 1

Given:-

→ Initial velocity of the body = 40m/s

→ Time taken to come to rest = 20 s

To find:-

→ Retardation of the body.

→ Distance travelled in given time.

Solution:-

In this case :-

• Final velocity of the body will be zero

as it finally comes to rest.

Let's calculate the acceleration of the car by using the 1st equation of motion :-

=> v = u + at

=> 0 = 40 + a(20)

=> -40 = 20a

=> a = -40/20

=> a = -2m/s²

[Here -ve sign represents retardation ]

Now, let's calculate the distance travelled by the body by using the 2nd equation of motion :-

=> s = ut + ½at²

=> s = 40(20) + ½(-2)(20)²

=> s = 800 + ½(-2)(400)

=> s = 800 + 200(-2)

=> s = 800 - 400

=> s = 400 m

Thus :-

• Retardation of the body is 2m/s² .

• Distance travelled in given time

is 400m .

Some Extra Information:-

The 3 equations of motion, for a body moving with uniform acceleration are :-

• v = u + at

• s = ut + ½at²

• v² - u² = 2as