Fewpal
0 votes
21 views
in Laws of Motion and Friction by (249 points)
closed by

A person of mass M kg is standing on a lift. If the lift moves vertically upwards according to given v-t graph then find out the weight of the man at the following instants :(g=10m/s). Find his apparent weight at t=12 seconds.

1 Answer

+1 vote
by (71 points)
selected by
 
Best answer
From t=10 sec to t=12 sec

s = area under v-t graph

   = 1/2 * 4 * 20 = 40 mt

also s = ut + 1/2 at^2

from solving this you will get a = -5 m/s^2

So the lift is descending with a acc. = 5 m/s^2

So the forces on the person are g downwards ( w.r.t ground ) and a upwards  ( w.r.t ground ) so net force on person w.r.t ground is g - a = 10 - 5 = 5 m/s^2

Hence the apparent weight is W = m * a

= M * 5 = 5M

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...