Solved Examples on Effects of force

Example 1: Net force applied on a car with mass of 1000 kg is 10000 N, what will be its acceleration ?

Solution:

Given,

m = 1000 kg

F = 10000 N

we have F = m × a;

10000 = 1000 × a

⇒ a = 10000/ 1000

⇒ a = 10 m/s²

Hence acceleration of car would be 10 m/s² .

Example 2: A ball of mass 4 kg is moving with the initial speed of 5m/s and then suddenly comes to rest in 0.02 sec. Calculate the force that changed the state of the moving ball ?

Solution:

Given,

initial velocity u = 5 m/s

final velocity v = 0 m/s

time t = 0.02 sec

mass m = 4 kg

from initial velocity and final velocity we can find the acceleration of body

a = (v-u)/t = (0-5)/0.02 = -250 m/s² .

Negative sign shows that it is retardation.

now to calculate force we have formula as

F = m × a

⇒ F = 4 × 250

⇒ F =1000 N

Hence force that changed state of ball is 1000 N.

Example 3: A 15 kg body slides along the floor with a constant velocity. What is the net force on the block ?

Solution:

Given,

M = 15 kg

It is given that body is sliding with constant velocity hence initial velocity is same as final velocity .

acceleration a = (v-u)/t = 0 m/s² .

Net force acting on the body is F = m × a = 15 × 0 = 0 N.

Example 4: A ball is rolling with linear acceleration of 2 m/s² and the net force acting on it is 39 N, calculate the mass of ball.

Solution:

Given,

F = 39 N

a = 2 m/s²

F = m × a

⇒ 39 = m × 2

⇒ m = 39 / 2 = 19.5 kg

Hence the mass of the ball is 19.5 kg.

Example 5: A person is pushing box to right with a force of 50 N and another person is applying force of 25 N on same box in left direction , what is the magnitude of net force acting on the body ?

Solution:

Given F₁ = 50 N and F₂ = 25 N

both forces are acting in opposite direction so net magnitude of force acting on body is

F = 50 – 25 = 25 N .

Force is a push or pull acting on a body. In day to day life, we encounter powerful effects of force all around us. From walking, lifting, writing, closing and opening of doors, we are surrounded by the effects of force. It is one of the fundamental physical phenomena. We can’t imagine our lives without force. Even planetary motion and various other natural activities are guided by the force.

In this article, we are going to learn about effects of force with a basic introduction of force and its types.