Question

A force $F$ acts on a body at an angle $\theta$ with horizontal and produces displacement '$s$' in horizontal direction. Match the column for work done by force $F$ for a given angle $\theta$:

List I	List II
a)$\theta =0^0$	e)$Fs$
b)$\theta ={120}^0$	f)$0$
c)$\theta ={60}^0$	g)$\frac{Fs}{2}$
d)$\theta ={90}^0$	h)$-\frac{Fs}{2}$

• A. $a\to e,b\to h,c\to g,d\to f$
• B. $a\to h,b\to e,c\to g,d\to f$
• C. $a\to h,b\to e,c\to f,d\to g$
• D. $a\to g,b\to f,c\to e,d\to h$

Answer 1

The correct option is A $a\to e,b\to h,c\to g,d\to f$

$W.D=\overrightarrow{F}.d\overrightarrow{s}$

$=F\times S\times cos\theta$

(1) $\theta =0^o;W.D=Fs$

(2) $\theta ={120}^o;W.D=\frac{-Fs}{2}$

(3) $\theta ={60}^o;W.D=\frac{Fs}{2}$

(4) $\theta ={90}^o;W.D=0$