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View Full Version : Apparent Weight & Roller Coasters - PLEASE HELP!


maddiegillis
Dec 30, 2012, 11:42 PM
A 60.0 kg person is riding through a circular dip of radius 16 m on a roller coaster at a speed of 14.0 m/s. what will be the person's weight at the bottom of the dip? While moving up the roller coaster the student suddenly starts to feel weightless, calculate the speed at that point on the roller coaster.

When questions ask you to find the apparent weight, are they asking you to find the normal force? Because I thought the force of gravity was always constant?

Thank you so much I really appreciate it! :)

ebaines
Jan 2, 2013, 11:38 AM
The apparent weight is the sum of the normal forces acting on his body due to gravity (his "true" weight W=mg) plus the normal force due to centripedal acceleration. Be careful to consider the direction of these forces - at the bottom of the loop these two forces add together and at the top of the loop the total normal force is the centripdeal force minus the force due to gravity.

maddiegillis
Jan 2, 2013, 12:29 PM
Thank you so much! I just did the question following the way you explained it, would you be able to verify if my solutions are correct?

For the apparent weight at the bottom of the dip I got an answer of 1324N.

For the velocity when the person feels weightless I calculated an answer of 12.5 m/s

ebaines
Jan 2, 2013, 12:41 PM
I agree with your answers - very good!