Question

The figure shows a pair of pin-jointed gripper - tongs holding an object weighing 2000 N. The coefficient of friction $\left(\mu \right)$ at the gripping surface is 0.1. XX is the line of action of the input force and YY is the line of application of gripping force. If the pin-joint is assumed to be frictionless, the magnitude of force F required to hold the weight is

• A. 1000 N
• B. 2000 N
• C. 2500 N
• D. 5000 N

Answer 1

The correct option is D 5000 N

FBD of object

$2f=2000$
$f=1000$
$=\mu N$
$=0.1\times N$
$N=10000N$

Consider one tong of grippers. Taking the net moment about the hinge point of gripper tong zero (because it is equilibrium).

As we are taking moment about hinge so no need to consider hinge reaction.

$F\times 300=N\times 150$

$F=\frac{N}{2}=\frac{10000}{2}$

$=5000N$