Question

A 1 m long uniform beam of 2 kg mass is being lifted vertically up by a force F at the 100 cm mark. What is the minimum force to do so?

• A. 1 N
• B. 2 N
• C. 10 N
• D. 20 N

Answer 1

Answer: (C)

10 N

The force F will be minimum when moment of force F is equal to the moment of force of the center of gravity.

$\Rightarrow F\times \frac{100}{100}m=(2kg\times 10m/s^2)\times \frac{50}{100}m$

$\Rightarrow F=\frac{20\times 0.50}{1}N$

$\Rightarrow F=10N$

Hence, the correct option is C.