Open In App

How to find Impulse with force and time?

Improve
Improve
Like Article
Like
Save
Share
Report

Impulse can be calculated by multiplying force with time. The formula for calculating impulse is J = FΔt where J is the impulse, F is the force applied and t is the time duration for which the force is applied. The SI unit of impulse is Newton-seconds (N·s). In this article we are going to learn what is impulse, formula for calculating impulse and some sample problem for calculating impulse.

Impulse

Impulse is defined as a huge force applied to an object over a time interval. It can be interpreted as a large force that acts for a very short period of time. When a net force is applied to an object, it affects its momentum during the course of the force’s application. To put it another way, impulse is the rate at which momentum changes. If an object has a big momentum shift during a short time period, a large net force must have been applied to it. This forms the basis for the concept of impulse.

Impulse Formula

Impulse of an object is equal to the product of the average and the time interval during which the force is applied. The change in momentum is equal to the impulse. It is denoted by the symbol J. It is a vector quantity, means it has both direction and magnitude as well. Its standard unit of measurement is newton seconds (Ns) and dimensional formula is given by [M1L1T-1].

J = Δp = FΔt

where,

J is the impulse value,

Δp is the change in momentum of an object,

F is the force acting on the object,

Δt is the time interval of acting force.

Sample Problems

Problem 1. Calculate the impulse if a force of 200 N is exerted on an object for 5 s.

Solution:

We have,

F = 200

Δt = 5

Using the formula we get,

J = FΔt

= 200 (5)

= 1000 Ns

Problem 2. Calculate the impulse if a force of 120 N is exerted on an object for 3 s.

Solution:

We have,

F = 120

Δt = 3

Using the formula we get,

J = FΔt

= 120 (3)

= 360 Ns

Problem 3. Calculate the force exerted on an object if the impulse is 1600 Ns for 2 s.

Solution:

We have,

J = 1600

Δt = 2

Using the formula we get,

J = FΔt

=> F = J/Δt

=> F = 1600/2

=> F = 800 N 

Problem 4. Calculate the force exerted on an object if the impulse is 2500 Ns for 10 s.

Solution:

We have,

J = 2500

Δt = 10

Using the formula we get,

J = FΔt

=> F = J/Δt

=> F = 2500/10

=> F = 250 N 

Problem 5. Calculate the time for which a force of 350 N is exerted on an object to create an impulse of 2100 Ns.

Solution:

We have,

J = 2100

F = 350

Using the formula we get,

J = FΔt

=> Δt = J/F

=> Δt = 2100/350

=> Δt = 6 s

Problem 6. Calculate the time for which a force of 700 N is exerted on an object to create an impulse of 5600 Ns.

Solution:

We have,

J = 5600

F = 700

Using the formula we get,

J = FΔt

=> Δt = J/F

=> Δt = 5600/700

=> Δt = 8 s

Problem 7. Calculate the impulse of an object of mass 3 kg if its velocity changes from 10 m/s to 25 m/s.

Solution:

We have,

m = 3

vi = 10

vf = 25

Using the formula we get,

J = m Δv

= 3 (25 – 10)

= 3 (15)

= 45 Ns


Last Updated : 07 Mar, 2024
Like Article
Save Article
Previous
Next
Share your thoughts in the comments
Similar Reads