Question

A sphere of weight w is hanging against a wall as shown in Figure. Which of the relations is incorrect?

• A. $\overline{T}+\overline{W}+\overline{N}=0$
• B. $T\sin \theta =N$
• C. $T=W/\cos \theta$
• D. $W-N=T/\cos \theta$

Answer 1

The correct option is D $W-N=T/\cos \theta$

Since the sphere is in equilibrium, resultant sum of all forces on it must add to 0. Hence option A is correct.

For vertical equilibrium, vertical component of tension must be equal to weight of the sphere. Hence option B is correct.

For horizontal equilibrium, horizontal component of tension must be equal to normal force from wall on the sphere. Hence option C is correct.