Question

An elevator weighs 4000kg. When the upward tension in the supporting cable is 48000N,what is the upward acceleration? Starting from rest, how far does it rise in 3 seconds?

Answer 1

Mass of elevator = 4000 kg

Weight of elevator = Mass × gravity

Weight = 4000 × 9.8

Weight = 39200 N

Upward Force applied = 48000 N

F(net) = 48000 - Weight

F(net) = 48000 - 39200

F(net) = 8800 N

Also, F(net) = mass (m) × acceleration (a)

$a = \frac{F_n_e_t}{m}$

$a = \frac{8800}{4000}$

a = 2.2 m/s^2

Now,

Initial velocity (u) = 0 m/s

Time = 3 seconds

H = ?

$H = ut + \frac{1}{2}\times a \times t^2$

$H = 0 + \frac{1}{2} \times 2.2 \times 3^2$

H = 9.9 m

Hence, the elevator is raised by 9.9 m.

Answer 2

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