(i) Give an example of an object that has three forces acting on it, and (1) accelerates, (2) moves at constant (nonzero) velocity, and (3) remains at rest. (ii) In terms of work done distinguish between conservative and non-conservative force.

A crate of mass 9.0 kg is pulled up a rough incline with an initial speed of 1.42 m/s. The pulling force is 110 N parallel to the incline, which makes an angle of 20.6° with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 4.92 m. (a) How much work is done by the gravitational force on the crate? |-152.68 (b) Determine the increase in internal energy of the crate-incline system owing to friction. 33.02 A careful free-body diagram of the crate may help you determine the magnitude of the friction force. J (c) How much work is done by the 110-N force on the crate? 541.2 (d) What is the change in kinetic energy of the crate? 355.5 You appear to have calculated the change in kinetic energy correctly using your incorrect results from the previous parts. J (e) What is the speed of the crate after being pulled 4.92 m? 9 You appear to have calculated the speed correctly using your incorrect result from part (d). m/s

(c) A 4.0 kg bundle starts up a 30° incline with 128 J of kinetic energy. How far will it slide up the incline if the coefficient of kinetic friction between bundle and incline is 0.30?

(II) A 380-kg piano slides 3.9 m down a 27° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline (Fig. 7-21). Determine: (a) the force exerted by the man, (b) the work done by the man on the piano, (c) the work done by the force of gravity, and (d) the net work done on the piano. Ignore friction. ania W(o FIGURE 7-21 Problem 11.

Both

A 6.00 kg package slides 2.50 m down a long ramp that inclined 20° below [2.) the norizontal. The coefficient of kinetic friction between the package and the ramp is Hk = 0.23. Calculate (a) the work done on the package by friction; (b) the work done on the package by gravity3; (c) the work done on the package by the normal force; (d) the total work done on the package. (e) If the package has a speed 3.00 m/s at the top of the ramp, what is its speed after slidinga.50 m down the ramp?

(II) A 975-kg sports car accelerates from rest to 95 km/h in6.4 s. What is the average power delivered by the engine?

Consider a 900-kg car being pulled by a 1200-N force applied at anangle of 30 degrees with the horizontal. The car traveled a total distance of 5.0meters forward. The coefficient of kinetic friction between the road and the tires is0.25. Determine the work done (in Joules) by each of the external forces acting onthe car. Please show full solution.