A physics professor is pushed up a ramp inclined upward at an angle 34.0degree a

Question

A physics professor is pushed up a ramp inclined upward at an angle 34.0degree above the horizontal as he sits in his desk chair that slides on frictionless rollers. The combined mass of the professor and chair is 81.0 kg . He is pushed a distance 2.95 m along the incline by a group of students who together exert a constant horizontal force of 609 N . The professor's speed at the bottom of the ramp is 1.60 m/s. Use the work-energy theorem to find his speed at the top of the ramp. My Answers Give Up Provide Feedback

Explanation / Answer

work = force * displacement in the direction of the force

work done on the object = 609*2.95 / Cos34

= 1796.55 *0.82903757

= 1489.4 J

kinetic E = 1/2mv^2

initial kinetic energy =81*(1.6)^2 / 2 = 103.68 J

gravitation potential is 0 at the bottom of the ramp

G. Potential E = mgh

final potential energy = 81 * 9.8 * 2.95*Sin34

= 2341.71 * 0.5591929

= 1309.46 J

final: total energy = 1489.4 + 103.68 = 1593.08 J

final kinetic energy = total energy - potential energy

= 1593.08 - 1309.46

= 283.62 J

E = 1/2mv^2

283.62 = 81 * v^2 /2

v^2 = 7

v = 2.64 m/s

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