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1. A roller-coaster car has a mass of 499 kg when fully loaded with passengers.

ID: 2253328 • Letter: 1

Question

1. A roller-coaster car has a mass of 499 kg when fully loaded with passengers. The path of the coaster from its initial point shown in the figure to point B involves only up-and-down motion (as seen by the riders), with no motion to the left or right. Assume the roller-coaster tracks at points A and B are parts of vertical circles of radius r1 = 10.0 m and r2 = 15.0 m, respectively.

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A roller-coaster car has a mass of 499 kg when fully loaded with passengers. The path of the coaster from its initial point shown in the figure to point B involves only up-and-down motion (as seen by the riders), with no motion to the left or right. Assume the roller-coaster tracks at points A and B are parts of vertical circles of radius r1 = 10.0 m and r2 = 15.0 m, respectively. If the vehicle has a speed of 19.7 m/s at point A, what is the force exerted by the track on the car at this point? What is the maximum speed the vehicle can have at point B and still remain on the track? A skydiver of mass 77.0 kg jumps from a slow-moving aircraft and reaches a terminal speed of 54.2 m/s. What is her acceleration when her speed is 30.0 m/s? What is the drag force on the skydiver when her speed is 54.2 m/s? What is the drag force on the skydiver when her speed is 30.0 m/s?

Explanation / Answer

1.

On point A, the force exertad by the track is the normal which is also the centripetal force and we have:

N-mg =mV^2/r1

=>N =m(g+V^2/r1)

N=499(9.8+19.7^2/10)

N=24256 N

b)

On B, the normal force pointing downwars along with gravity should go to zero to allow the roller-coaster to remain in track, gravity is thus the only centripetal force: