The position-time graph of a body of mass 2 kg is as given in the figure. What is the impulse on the body at t=0 s and t=4 s.
1.
1.5kg-m/s
2.
−1.5kg-m/s
3.
0.67kg-m/s
4.
−0.67kg-m/s
Hint: Impulse is equal to change in momentum.
Step 1: Find impulse at t = 0 sec
Given, the mass of the body (m) = 2 kg
From the position-time graph, the body is at x = 0 when t = 0. i.e., body is at rest ∴ Impulse at t = 0 s, is zero
Step 2: Find impulse on the body at t = 4 sec
From t = O s to t = 4 s, the position-time graph is a straight line, in which that body moves with uniform velocity.
Beyond t = 4s, the graph is a straight line parallel to the time axis i.e., the body is at rest (v = 0).
The velocity of the body = slope of the position-time graph