# Power Transmitted by a Shaft in Torsion

## Trending Questions

**Q.**Two shafts A and B are made of the same material. The diameter of shaft B is twice that of shaft A. The ratio of power which can be transmitted by shaft A to that of shaft B is (If maximum shear stress remains the same)

- 12
- 14
- 18
- 116

**Q.**If the diameter of a shaft subjected to torque alone, is doubled, then the horse power P can be increased to

- 16P
- 8P
- 4P
- 2P

**Q.**What is the power transmitted by a 100 mm diameter soild shaft at 150 rpm without exceeding a maximum stress of 60 N/mm2?

- 187.5 kW
- 18.75 kW
- 1.875 kW
- 1875 kW

**Q.**If a shaft is turning at N r.p.m and the mean torque to which the shaft is subjected is T N-m, the power transmitted by the shaft in kW would be

- 2πNT45000
- 2πNT60000
- 2πNT30000
- 2πNT33000

**Q.**A solid shaft of 80 mm diameter is transmitting 100 kW of power at 200 r.p.m. The maximum shear stress induced in the shaft will nearly be

- 60 N/mm2
- 56 N/mm2
- 52 N/mm2
- 48 N/mm2

**Q.**A shaft turns at 150 rpm under a torque of 1500 Nm. Power transmitted is

- 15π kW
- 10π kW
- 7.5π kW
- 5π kW

**Q.**A solid shaft rotating at 180 rpm subjected to a mean torque of 5000 N-m. What is the power transmitted by the shaft in kW?

- 25 π
- 20 π
- 60 π
- 30 π

**Q.**

**Assertion (A) :**A hollow circular shaft has more power transmitting capacity than a solid shaft of same material and same weight per unit length.

**Reason(R):**In a circular shaft, shear stress developed at a point due to torsion is propotional to its radial distance from the centre of the shaft.

- both A and R are true and R is the correct explanation A
- both A and R are true but R is not a correct explanation of A
- A is true but R is false
- A is false but R is true

**Q.**A hollow steel shaft has outside diameter d and inside diameter d/2. The value of d for the shaft, if it has to transmit 200 hp at 105 rpm with a working shear stress of 420 kg/cm2, is

- 5.6 cm
- 2.6 cm
- 12.1 cm
- 15.5 cm

**Q.**A circular shaft rotates at 200 rpm and is subject to a torque of 1500 Nm. The power transmitted would be

- 10 π kW
- 15 π kW
- 20 π kW
- 30 π kW

**Q.**A metal shaft of solid circular section rotates at 160 rpm and is subjected to a torque of 1500 Nm. What is the power, in kW, transmitted by the shaft?

- 32 π
- 16 π
- 12 π
- 8 π

**Q.**A solid shaft transmits 150 kW at a shear stress of 70 MPa running at a frequency of 3 Hz. What will be the shear stress when the frequency is 1.5 Hz?

- 35 MPa
- 50 MPa
- 57 MPa
- 140 MPa

**Q.**Two steel shafts A and B are used for transmitting power. The ratio of revolutions of shafts i.e., NANB=2. The ratio of torques on shafts i.e., TATB=12. The ratio of the horse power transmitted by the shafts i.e. PAPB would be

- 1/2
- 1/4
- 1
- 2

**Q.**A hollow shaft d0=2di (where d0 and di are the outer and inner diameters respectively) needs to transmit 20 kW power at 3000 RPM. If the maximum permissible shear stress is 30 MPa, d0 is

- 11.29 mm
- 22.58 mm
- 33.87 mm
- 45.16 mm

**Q.**

A car of mass 1000 kg travels at 12 m/s on a horizontal and the resistance to motion is 500 N. Find (c) the power developed by the engine.

**Q.**The power transmitted by a 75 mm diameter shaft at 140 r.p.m., subjected to a maximum shear stress of 60 N/mm2, is nearly

- 68 kW
- 70 kW
- 73 kW
- 76 kW

**Q.**

A pulley system has $\mathrm{MA}=4$. If a load of $10\mathrm{kgf}$ is pulley by a distance of $2\mathrm{m}$ in $10\mathrm{s}$, calculate the power developed by the effort.

$15\mathrm{w}$

$20\mathrm{w}$

$25\mathrm{w}$

$4.9\mathrm{w}$

**Q.**If a shaft rotates at 100 r.p.m and is subjected to a torque of 3000 N-m, the power transmitted in kW would be

- 30 π
- 15 π
- 20 π
- 10 π

**Q.**A motor driving a solid circular steel shaft transmits 40 kW of power at 500 rpm. If the diameter of the shaft is 40 mm, the maximum shear stress in the shaft is ______ MPa.

- 60.792