ISRO 2012 Mechanical Engineering Questions, Answers and Explanation

ISRO 2012 Mechanical Engineering Questions, Answers and Explanation

8. An elevator weighing 1000 kg attains an upward velocity of 4m/sec in two seconds with uniform acceleration. The tension (in N) in supporting cable will be (g = 9.8 m/sec²)

a) 1204 N

b) 9800 N

c) 2000 N

d) 11800 N

Answer

d) 11800

Explanation [Engineering Mechanics]

acceleration = change in velocity/time = 4/2 2 m/s²

Tension increases when the lift accelerate upwards and decreases when the lift accelerate downwards.

So tension in supporting cable = m(g+a) = 1000 (9.8+2) = 1000 x 11.8 = 11800 N