Question

a man of mass 50kg is standing in an elevator .if the elevator is moving up with acceleration g/3 thrn work done by normal reaction of the floor of the elevator on man when elevator moves by a distance 12m is​

Answer 1

Answer:

The work done by normal reaction of the floor is 8000 J.

Explanation:

Given : A man of mass 50 kg is standing in an elevator. If the elevator is moving up with acceleration g/3.

To find : Work done by normal reaction of the floor of the elevator on man when elevator moves by a distance 12 m ?

Solution :

The work done is given by,

$W=PE+KE$

$W=\frac{1}{2}mv^2+mgh$

$W=m(\frac{1}{2}v^2+gh)$ .....(1)

The mass m=50 kg

The distance s=12 m

The acceleration $a=\frac{g}{3}$

Using equation of motion,

$v_f^2-v_i^2=2as$

Substitute the value in the formula,

$v^2-0=2\times \frac{g}{3}\times 12$

$v^2=2\times \frac{10}{3}\times 12$

$v^2=80$

Substitute the value in equation (1),

$W=50(\frac{1}{2}\times 80+10\times 12)$

$W=50(40+120)$

$W=50(160)$

$W=8000$

Therefore, The work done by normal reaction of the floor is 8000 J.