Question

A student stands on a bathroom scale in an elevator at rest on the 64th floor of a building. The scale reads 836 N.

Answer 1

The answers to the problem are as follows:

  a) use f=ma. Mass of student is 836/9.8=85.3kg, force is 935-836=99N. Put it into the formula you will get a=99/85.3 

b)Use same formula. Force is 782-836=-54 so put it into formula a=-54/85.3 

c)Stopping would take longer as the acceleration is smaller 


I hope my answer has come to your help. God bless and have a nice day ahead!

Answer 2

Answer:

Part a)

$a = 1.16 m/s^2$

Part b)

$a = 0.63 m/s^2$

Explanation:

Part a)

When elevator is moving upwards then reading of the scale is measurement of normal force

it is given as

$F_n - mg = ma$

$935 - 836 = \frac{836}{9.81} a$

$a = 1.16 m/s^2$

Part b)

When elevator decelerate then the scale reading is less than the actual weight as its acceleration will have reverse direction

So we will have

$F_n - mg = -ma$

$782 - 836 = -\frac{836}{9.81} a$

$a = 0.63 m/s^2$