If →F is the force acting on a particle having position vector →r and →τ be the torque of this force about the origin, then:
1. | →r⋅→τ≠0 and →F⋅→τ=0 |
2. | →r⋅→τ>0 and →F⋅→τ<0 |
3. | →r⋅→τ=0 and →F⋅→τ=0 |
4. | →r⋅→τ=0 and →F⋅→τ≠0 |
1. | b2 | 2. | b4 |
3. | b8 | 4. | b3 |
A uniform rod of length 200 cm and mass 500 g is balanced on a wedge placed at 40 cm mark. A mass of 2 kg is suspended from the rod at 20 cm and another unknown mass m is suspended from the rod at 160 cm mark as shown in the figure. What would be the value of m such that the rod is in equilibrium?
(Take g=10 (m/s2)
1. | 16 kg | 2. | 112 kg |
3. | 12 kg | 4. | 13 kg |
1. | wxd | 2. | wdx |
3. | w(d−x)x | 4. | w(d−x)d |
A non-uniform bar of weight W is suspended at rest by two strings of negligible weight as shown in the figure. The angles made by the strings with the vertical are 36.9∘ and 53.1∘ respectively. The bar is 2 m long. The distance d of the center of gravity of the bar from its left end is:
(Take sin36.9∘=0.6 and sin53.1∘=0.8)
1. 69 cm
2. 72 cm
3. 79 cm
4. 65 cm
To maintain a rotor at a uniform angular speed of 200 rad/s, an engine needs to transmit a torque of 180 N-m. What is the power required by the engine?
1. 33 kW
2. 36 kW
3. 28 kW
4. 76 kW