Question

Only (a).

(7.7.40) In the picture below, an 80.0 kg mass is dragged up an incline by a cable attached to a winch. The position of the mass as a function of time is given by x(t) = Bt^4, where B = 0.03 m/s^4. x is measured by an axis which runs along the incline, as shown, x = 0 at the bottom of the incline and x = 10.0 m at the top of the incline. The cable is always parallel to the incline. The coefficienct of kinetic friction between the mass and the incline is 0.30. Find (a) The average power given to the mass by the cable during the entire process by which the mass is dragged to the top. (b) The instantaneous power to given to the mass by the cable as the mass passes through x = 7.0 m

Answer 1

Calculate the sum of forces acting along the cable. F_ (w×9.81) cos 60°17-80a μ.N-80x 9.8 1 cos 60°+T-80a (0.3x. 680 N). .392.1:7. : :80a T 80a 594 dt =- ( Bt dt Calculate the acceleration of the mass ch dt dt 12Bt Substitute 12Bt for a. T 80a + 5 94 -28.8t2 594