Acceleration in an Elevator: Solving Newton's Second Law Problem

AI Thread Summary
To solve the problem involving Newton's Second Law in an elevator scenario, begin by analyzing the forces acting on the student at different points in the elevator's motion. The student's weight readings indicate variations in acceleration: an increase to 1050 N suggests upward acceleration, while a drop to 588 N indicates downward acceleration. Use the equation for acceleration, which is net force divided by mass, applying the gravitational force equation as needed. Drawing free-body diagrams for each situation will help clarify the forces involved. This structured approach will lead to determining the acceleration at both the beginning and end of the elevator trip.
hghwinds
Messages
2
Reaction score
0
Hi, I'm having trouble with a problem dealing with Newton's Second Law, and was wondering if anyone could give me a hint as to how I should solve it (general equation, process, whatever)? I'm not asking for somebody to solve it, I just need some help...:smile:


Homework Statement


A student, standing on a scale in an elevator at rest, sees that his weight is 840 N. As the elevator rises, his weight increases to 1050 N, then returns to normal. When the elevator slows to a stop at the 10th floor, his weight drops to 588 N, then returns to normal. Determine the acceleration at the beginning and end of the trip.

Homework Equations



acceleration= net force/mass and maybe Fg= ge * mass

The Attempt at a Solution

 
Physics news on Phys.org
This is a two part problem: treat the beginning and end of the trip as two separate problems. For each situation, draw a free-body diagram of the forces acting on ElevatorMan, then algebraically add up the forces associated with each arrow.
Welcome aboard, and hope that helps!
 
Alright, thanks so much!
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top