Question

When a body is moving vertically up with constant velocity, then match the following.

Column I		Column II
i	Work done by lifting force is	a	negative
ii	Total work done by all the forces is	b	positive
iii	Work done by gravity	c	zero
iv	Work done by lifting force $+$ work done by gravity force	d	higher positive values

• A. i $\rightarrow$ c; ii $\rightarrow$ b; iii $\rightarrow$ a; iv $\rightarrow$ d
• B. i $\rightarrow$ b; ii $\rightarrow$ c; iii $\rightarrow$ a; iv $\rightarrow$ c
• C. i $\rightarrow$ d; ii $\rightarrow$ c; iii $\rightarrow$ a; iv $\rightarrow$ a
• D. i $\rightarrow$ b; ii $\rightarrow$ c; iii $\rightarrow$ d; iv $\rightarrow$ a

Answer 1

Answer: (B)

As the force and direction of movement is in the same direction, so work done by lifting force is positive.
Due to constant velocity total work must be zero.
As gravity acts downwards, so work done by it is negative.
Here we have only two forces, lifting force and gravity, which are operational. As the object is moving with constant velocity, net work done by these forces has to be zero.