Given Data
we have a person whose mass is m= 79 kg. and rides in the elevator.
velocity vs time graph is given.
first look at the free body diagram of a person
now look all the forces which are acting on a person
person in an elevator that is moving upwards
we can write the equation as
Here N is a normal reaction by the bathroom scale, mg is wight force and a acceleration of the elevator
we can write above equation as
now we have to calculate acceleration
we can see the graph
for the increasing the velocity we can write acceleration as
now we can write put the acceleration into equation 1
we have
at t =4 seconds no acceleration then a=0
then we can write
similarly for t=8 seconds
we have
from equation (1) we can write as