A 3640 lb roller coaster experiences a constant air-resistance force of 26 lb and a constant friction force of 20 lb. What initial velocity is required for the coaster to make it around the 0.57 mile track and coast to a stop at its starting location?

Answer 1

The initial kinetic energy must equal the friction work done in traveling 0.57 miles (3010 feet).

If you want the speed in feet/second, the mass must be in slugs, and the distance X must be in feet.

3640 lb = 113 slugs

(M/2) V^2 = 46 lb*X

Solve for V.

V^2 = 2*46*3010/113 = 2451 ft^2/s^2

If you are not familiar with the use of slugs for mass, do the problem with force, mass and distance in SI units, to get the velocity in m/s.

Answer 2

Thank you very much