Mechanical Aptitude Ultimate Questions and Answers 3

Question 1

A belt drive system has a driving pulley of 10 cm diameter spinning at 1,800 RPM. If the driven pulley must spin at 600 RPM, what diameter should it be?

Accepted Answer

30 cm

Answer

20 cm

Answer

40 cm

Answer

60 cm

Question 2

A lever arm is 2 meters long with the fulcrum 0.5 meters from the load. If the load is 400N, what effort force is needed to balance it?

Accepted Answer

133.3N

Answer

100N

Answer

200N

Answer

266.7N

Question 3

A pipe with internal pressure of 500 kPa has an inner diameter of 200 mm and a wall thickness of 10 mm. What is the hoop stress in the pipe wall?

Accepted Answer

5 MPa

Answer

2.5 MPa

Answer

10 MPa

Answer

50 MPa

Question 4

An electric motor draws 10 amps at 240 volts and produces 2 kW of mechanical output. What is the motor's efficiency?

Accepted Answer

83.3%

Answer

75.3%

Answer

80.0%

Answer

92.0%

Question 5

What is the factor of safety if a component's ultimate tensile strength is 450 MPa and the maximum working stress is 150 MPa?

Accepted Answer

3.0

Answer

2.0

Answer

4.5

Answer

6.0

Question 6

A heat engine operates between temperatures of 600K (hot reservoir) and 300K (cold reservoir). What is its maximum possible (Carnot) efficiency?

Accepted Answer

50%

Answer

25%

Answer

75%

Answer

100%