A person stands on a scale inside an elevator at rest. The Scale reads 800N. a) What is the person's mass? (b) The elevator accelerates upward momentarily scale read then? (c) The elevator then moves with a steady speed of 5m/s. What Does the scale read?

Anish Buchanan

Anish Buchanan

Answered question

2021-03-09

A person stands on a scale inside an elevator at rest. The Scale reads 800N.
a) What is the persons

Answer & Explanation

Khribechy

Khribechy

Skilled2021-03-10Added 100 answers

mass m=Wg
= weight/acceleration due togravity
=8009.8=81.6326 kg
image
Key idea is the scale reading is equal to the magnitude of normal force N on the passenger from the scale.
NFg=ma
N=Fg+ma
This tells us that the scale reading , which is equal to N depends on the vertical acceleration a of the cab. Substituting mg for Fg gives us N = mg +ma = m (g+a)
For any choice of acceleration. a. if it accelerates up the weight will be more because a +ve
if it accelerates downward then weight will decrease because a is - ve then.
If moving with constant speed a =0 so the weight will remain the same as 800N
When suddenly accelates up let us say acceleration = a
Then scale reads m(g + a) = 81.83( 9.8 +a)
When it is moving with constant speed means not moving with any additional acceleration . a = 0
Scale reading = mg = 800N

Do you have a similar question?

Recalculate according to your conditions!

Ask your question.
Get an expert answer.

Let our experts help you. Answer in as fast as 15 minutes.

Didn't find what you were looking for?