Question

Acar initially at rest starts moving with an
acceleration of 4 ms. The time in which it
picks up a velocity of 72 ms is dash second​

Answer 1

It is given that car initially at rest moving with an acceleration of 4 m/s² acquires a velocity of 72 m/s

We have to find time taken by car to acquire that velocity.

Solution

As the car is initially at rest, so initial speed i.e. u = 0 m/s

Final velocity (v) = 72 m/s

Acceleration (a) = 4 m/s²

★ Using 1st equation of motion :

➝ v = u + at

Putting values :

➝ 72 = 0 + 4t

➝ 72 = 4t

➝ t = 72/4

➝ t = 18 seconds.

Hence, time taken by car to acquire that velocity = 18 seconds.

________________________________

★ Some more equations :

➼ s = ut + ½ at²

➺ h = ut + ½ gt²

➼ v² - u² = 2as

➺ a = (v - u)/t

Answer 2

Answer:

Given :

• Acceleration = a = 4 m/s²
• Initial velocity =  0 m/s
• Final velocity = 72 m/s

To Find :

• Time taken to pickup a velocity of 72 m/s.

Solution :

We know the first equation of motion,

v = u + at

⇒ 72 = 0 + (4)(t)

⇒ 72 = 4t

⇒ t = 72/4

⇒ t = 18 seconds.

Hence, the time taken by the car to pickup a velocity of 72 m/s is 18 seconds.

MORE EQUATIONS OF MOTION :

1. v = u + at
2. s = ut + 1/2 at²
3. v² - u² = 2as