The electric motor of a model train accelerates the train from rest to 0.740 m/s in 25.0 ms. The total mass of the train is 575 g. Find the average power delivered to the train during its acceleration

When an automobile moves with constant speed down a highway, most of the power developed by the engine is used to compensate for the mechanical energy loss due to frictional forces exerted on the car by the air and the road. If the power developed by the engine is 195 hp, estimate the total friction force acting on the car when it is moving at a speed of 30 m/s. One horsepower equals 746 W.

A shopper pushes a grocery cart 39.25 m  on level ground, against a 37.06 N frictional force. The cart has a mass of 19.79 kg.  He pushes in a direction 24.67º below the horizontal. If the initial velocity was 1.78 m/s, and final speed was 16.88 m/2. What is the work done by the pushing force in unit of Joule?

A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 2.37 x 105 N. In being launched from rest it moves through a distance of 80.6 m and has a kinetic energy of 4.56 x 107 J at lift-off. What is the work done on the jet by the catapult?

The electric motor of a model train accelerates the train from rest to 0.760 m/s in 18.0 ms. The total mass of the train is 880 g. Find the average power delivered to the train during its acceleration.

A 1.4 kg textbook is thrown out of a window at 8.67 m/s and directed at an angle of 50.1° above horizontal. The window is 6.26 m above the ground. The textbook strikes the ground at a speed of 10.2 m/s. How much work is done on the textbook by air-resistance?

A 3.30-kN piano is lifted by three workers at a constant speed to an apartment 27.3 m above the street using a pulley system fastened to the roof of the building. Each worker is able to deliver 141 W of power, and the pulley system is 75.0% efficient (so that 25.0% of the mechanical energy is lost due to friction in the pulley). Neglecting the mass of the pulley, find the time required to lift the piano from the street to the apartment. min

The electric motor of a model train accelerates the train from rest to 0.830 m/s in 20.5 ms. The total mass of the train is 875 g. (a) Find the minimum power delivered to the train by electrical transmission from the metal rails during the acceleration. W (b) Why is it the minimum power?

Yosemite Falls in California is about 0.740 km high. What average power would it take for a 73.0-kg person to hike up to the top of Yosemite Falls in 1.50 h?

A 1.50 × 103-kg car starts from rest and accelerates uniformly to 18.0 m/s in 12.0 s. Assume that air resistance remains constant at 400 N during this time. Find (a) the average power developed by the engine and (b) the instantaneous power output of the engine at t = 12.0 s, just before the car stops accelerating.