Question

A particle is moving along a straight line. Its displacement time graph is shown.

Column I		Column II
i.	Work done on particle from 0 to $t_1$	p.	Positive
ii.	Work done on particle from $t_1$ to $t_2$	q.	Negative
iii.	Work done on particle from $t_2$ to $t_3$	r.	Zero
iv.	Work done on particle from $t_3$ to $t_4$	s.	Unpredictable

Now match the given columns and select the correct option from the codes given below.

• A. i—p, ii—q, iii—r, iv—s
• B. i—q, ii—r, iii—p, iv—s
• C. i—q, ii—q, iii—p, iv—r
• D. i—p, ii—r, iii—q, iv—s

Answer 1

Answer: (C)

For $0$ to $t_{1}$ slope is constant, speed is constant and so work done is zero.
For $t_{1}$ to $t_{2}$, slope is zero, speed is zero and so work done is zero.
For $t_{2}$ to $t_{3}$, slope is increasing, speed is increasing and so work done is positive.
For $t_{3}$ to $t_{4}$, slope is decreasing, speed is decreasing and so work done is negative.