Two physics questions on circular motion?

1.A 1900 kg car rounds a curve of radius 70 m banked at an angle of 12°. If the car is traveling at 84 km/h, will a friction force be required?


yes


no








If so, how much force? (Enter zero if there is no friction force





2.A jet pilot takes his aircraft in a vertical loop








(a) If the jet is moving at a speed of 1700 km/h at the lowest point of the loop, determine the minimum radius of the circle so that the centripetal acceleration at the lowest point does not exceed 6.0 g's.





(b) Calculate also the 78 kg pilot's effective weight (the force with which the seat pushes up on him) at the bottom of the circle.





(c) Calculate the pilot's effective weight at the top of the circle. (Assume the same speed.)

Two physics questions on circular motion?
1. the centripetal force needed is mv^2/r = 1900*(84*1000/3600)^2/70 = 1.48*10^4 N


if no friction, the resultant of gravity and the normal force is mgtan(12) = 1900*9.8*tan(12) = 3.96*10^3 N %26lt; 1.48*10^4 N


so friction force f is required where f cos(12) = 1.48*10^4 N - 3.96*10^3 N = 1.08*10^4 N


f = 1.10*10^4 N





2. a) v^2/r = 6g


r = v^2/(6g) = (1700*1000/3600)^2/(6*9.8) = 3.8*10^3 m


b) F - mg = mv^2/r = 6mg


F = 7mg = 7*70*9.8 = 4.8*10^3 N


c) F + mg = 6mg


F = 5mg = 5*70*9.8 = 3.4*10^3 N

orange