Question

Find the initial velocity of car which is stopped in
4s
by applying brakes. The acceleration
due to brake is 5 m/s²​

Answer 1

Answer:

20m/s

Explanation:

u=at => u=4*5=20

i hope this helps u

Answer 2

Question :-

Find the initial velocity of car which is stopped in 4 seconds by applying brakes . The acceleration due to brakes is - 5m/s²

Given :-

A car is stopped in 4s by applying brakes . The acceleration due to brakes is - 5 m/s²

Required to find :-

• Initial velocity of the car ?

Equation used :-

$\dagger \huge\boxed{ \text{v = u + at}}$

Solution :-

Given information :-

A car is stopped in 4s by applying brakes . The acceleration due to brakes is - 5 m/s²

we need to find the initial velocity of the car

So,

From the given information we can conclude that ;

• Final velocity of the car = 0 m/s

• Acceleration due to brakes = - 5 m/s²

• Time = 4 seconds

Using the 1st Equation of motion ;

That is

>> v = u + at

Here,

v = final velocity

u = Initial velocity

a = acceleration

t = time taken

By substituting the values we get ;

0 = u + (- 5 ) x 4

0 = u + (- 20 )

0 = u - 20

0 + 20 = u

20 = u

This implies ,

u = 20

Therefore,

Initial velocity of the car ( u ) = 20 m/s

Additional information :-

The 3 equations of the motion are ;

• 1. v = u + at

• 2. s = ut + ½at²

• 3. v² - u² = 2as

Negative acceleration is called with a specific name called retardation

( A perfect example for retardation is the above question )