Question

4.
In the figure given below, the position-time graph of a particle of mass 0-1 kg is shown.
The impulse at t=2 sec is
(1) 0-2 kgms
(2) -0.2 kgms
(3) 0.1 kgms-
(4) -0.4 kgms-'​

Answer 1

Given :

Mass of particle = 0.1kg

To Find :

Impulse at t = 2s

Solution :

At t = 2s,

the body has constant velocity.

We know that slope of position - time graph gives us velocity.

➠ u = slope (m)

➠ u = (4 - 0) / (2 - 0)

➠ u = 4/2

➠ u = 2 m/s

After t = 2s,

the body is at rest i.e., v = 0

■ Impulse is measured as the product of mass and change in velocity$.$

• J = m (v - u)

➛ J denotes impulse

➛ m denotes mass

➛ v denotes final velocity

➛ u denotes initial velocity

By substituting the values,

➠ J = 0.1 (0 - 2)

➠ J = 0.1 × (-2)

➠ J = -0.2 kg m/s

∴ (B) is the correct answer!