Question

1. An object of mass 4kg is moving with a velocity of 12ms 1. A
force is applied so that in 20s, it attains a velocity of 36ms?.
What is the force applied on the object? (4M)​

Answer 1

Answer:

$\bigstar{\bold{Force=4.8\:N}}$

Explanation:

$\Large{\underline{\underline{\bf{Given:}}}}$

• Mass of the body(m)  = 4 kg
• Initial velocity (u) = 12 m/s
• Final velocity = 36 m/s

$\Large{\underline{\underline{\bf{To\:Find:}}}}$

• Force applied on the body (F)

$\Large{\underline{\underline{\bf{Solution:}}}}$

→ First we need to find the acceleration (a) of the body

→ We know that acceleration is equal to rate of change of velocity and is given by

  a = ( v - u ) /t

→ Substituting the datas we get,

  a = ( 36 - 12 ) /20

  a = 24/20

  a = 1.2 m/s²

→ Hence acceleration of the body is 1.2 m/s²

→ By Newton's second law we know that

  F =  ma

→ Substituting the datas we get,

  F = 4 × 1.2

  F = 4.8 N

→ Hence the force acting on the object is 4.8 N

$\boxed{\bold{Force=4.8\:N}}$

$\Large{\underline{\underline{\bf{Notes:}}}}$

→ Newton's second law state that the rate of change of momentum is directly proportional to the force applied and the change takes place in the direction of the force.

 F =  ma