A tower crane has a hoist motor rated at 155 hp. If the crane is limited to using 67.0% of its maximum hoisting power for safety reasons, what is the shortest time in which the crane can lift a 5.50×103 kg load over a distance of 77.0 m?Assume the load is lifted at a constant velocity.

What average mechanical power (W) must a 76.5kg mountain climber generate to climb to the summit of a hill of height 405 m in 46.0 min? Due to in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the power that must be produced by the climber's body

A Ford F-150 pickup truck has a mass of 1950 kg.   One truck is equipped with an Ecoboost 2.7 liter V6 engine that produces a useful power output of 242 kW.        (a)  How long in seconds does it take the truck to start from rest and reach a speed of 12.5 m/s, assuming no friction effects and it is traveling on a level road?       (b)  How long will it take to reach the speed of 12.5 m/s from rest, if the truck also climbs a hill that has a height of 2.75 m?

A 1.50 ✕ 103-kg car starts from rest and accelerates uniformly to 19.9 m/s in 12.7 s. Assume that air resistance remains constant at 400 N during this time. (a) Find the average power developed by the engine. ___hp(b) Find the instantaneous power output of the engine at t = 12.7 s, just before the car stops accelerating. ____hp

A motorist driving a 1332-kg car on level ground accelerates from 20.0 m/s to 30.0 m/s in a time of 5.00 s. Ignoring friction and air resistance, determine the average mechanical power in watts the engine must supply during this time interval.

A tower crane has a hoist motor rated at 169 hp. If the crane is limited to using 65.0% of its maximum hoisting power for safety reasons, what is the shortest time in which the crane can lift a 5.50 x 10 kg load over a distance of 89.0 m? Assume the load is lifted at a constant velocity. t = S 仙登

A car accelerates uniformly from rest to 29.7 m/s in 8.07 s along a level stretch of road. Ignoring friction, determine the average power required to accelerate the car if (a) the weight of the car is 7.22 × 103 N, and (b) the weight of the car is 1.40 × 10^ N.

A 1.50 ✕ 103-kg car starts from rest and accelerates uniformly to 16.2 m/s in 11.1 s. Assume that air resistance remains constant at 400 N during this time. (a) Find the average power developed by the engine. hp(b) Find the instantaneous power output of the engine at t = 11.1 s, just before the car stops accelerating. hp

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.