E Consider an elevator car (lift) with a mass of 700kg which call carry up to 600kg of passengers. Use g = 10 ms?. An electric motor is used to raise the elevator with a full load from the ground floor to the third floor, 9 m higher, in 30 s. Calculate the total energy needed and the power of motor required. 12 MJ and 2kW 12400 Jand 2400 W 11700 Jand 3900 W 48 kJ and 2400 W

E Consider an elevator car (lift) with a mass of 700kg which call carry up to 600kg of passengers. Use g = 10 ms?. An electric motor is used to raise the elevator with a full load from the ground floor to the third floor, 9 m higher, in 30 s. Calculate the total energy needed and the power of motor required. 12 MJ and 2kW 12400 Jand 2400 W 11700 Jand 3900 W 48 kJ and 2400 W

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter7: Conservation Of Energy

Section: Chapter Questions

Problem 33P

See similar textbooks

Similar questions

Coal is lifted out of a mine a vertical distance of 50 m by an engine that supplies 500 W to a conveyer belt. How much coal per minute can be brought to the surface? Ignore the effects of friction.
The force exerted by a diving board is conservative, provided the internal friction is negligible. Assuming friction is negligible, describe changes in the potential energy of a diving board as a swimmer drives from it, starting just before the swimmer steps on the board until just after his feet leave it.
A typical automobile engine has an efficiency of 25 . Suppose that the engine of a 1000-kg automobile has a maximum power output of 140 hp. What is the maximum grade that the automobile can climb at 50 km/h if the frictional retarding force on it is 300 N?
Check Your Understanding What potential energy U(x) can you substitute in Equation 8.13 that will result in motion with constant velocity of 2 m/s for a particle of mass 1 kg and mechanical energy 1 J?
Using energy considerations and assuming negligible air resistance, show that a rock thrown from a bridge 20.0 m above water with an initial speed of 15.0 m/s strikes the water with a speed of 24.8 m/s independent of the direction tin own. (Hint. show that (Ki+Ui=Kf+Uf)
Repeat the preceding problem, but this time, suppose that the work done by air resistance cannot be ignored. Let the work done by the air resistance when the skier goes from A to B along the given hilly path be —2000 J. The work done by air resistance is negative since the air resistance acts in the opposite direction to the displacement. Supposing the mass of the skier is 50 kg, what is the speed of the skier at point B ?
What average power is generated by a 70.0-kg moun-tain climber who climbs a summit of height 325 in in 95.0 min? (a) 39.1 W (b) 54.6 W (c) 25.5 W (d) 67.0 W (e) 88.4 W
A 500-kg dragster accelerates from rest to a final speed of 110 m/s in 400 m (about a quarter of a mile) and encounters an average frictional force of 1200 N. What is its average power output in watts and horsepower if this takes 7.30s?
Using energy considerations, calculate the average force a 60.0-kg sprinter exerts backward on the track to accelerate from 2.00 to 8.00 m/s in a distance of 25.0 m, if he encounters a headwind that exerts an average force of 30.0 N against him.
Suppose you are jogging at constant velocity. Are you doing any work on the environment and vice versa?
Describe a situation in 4iich a force is exerted for a long time but does no work. Explain.
Check Your Understanding Fend the forces on the particle in Example 8.6 when kinetic energy is 1.0 J at x=0.