Question

The velocity acquired by a body moving with uniform
acceleration is 20 m/s in first 2 sec and 40 m/s in
first 4 sec. The initial velocity of the body is
(1) 40 m/s
(2) 20 m/s
(3) 10 m/s
(4) 0 m/s

Answer 1

Solution:

Given:

$\implies$ At t = 2s, v = 30 m/s

$\implies$ At t = 4s, v = 60 m/s

So:

$\boxed{\sf{Acceleration\:(a) = \frac{dv}{dt}}}$

$\implies$ a = (60-30) / (4-2)

$\implies$ a = 30/2

$\implies$ a = 15 m/s

We know that:

$\boxed{\sf{v = u +at}}$

Initial velocity will be calculated using:

$\boxed{\sf{u = v - at}}$

After two seconds:

$\implies$ u = 30 - 15 × 2

$\implies$ u = 30 - 30

$\implies$ u = 0

Thus,

Initial velocity (u) = 0 m/s

Therefore:

Correct option: (4) 0 m/s

_________________

Answered by: Niki Swar, Goa❤️

Answer 2

Hay mate here is your answer

Hope this help you .