Question

1. Power is a quantity Watts. 2. 1 hp is equal to 3. Energy is neither created nor destroyed, only determine the work done on an object, the angle 0, is measured between the Force and the 5. The SI units for Power are 6. Another name for the unit of Work, which is a N m, is called 7. Work done on an object slowing down is 8. Yo u push a lawn mower 6 times as far as your friend but you only exert the force. How much more work do you do? 9. Kinetic Energy depends on both Mass and 10. Two bullets have identical masses, but bullet A travels 4 times faster than bullet B. How much more KE does A have? 11. Find the speed of an 8.0 x 10'kg jet whose Kinetic Energy is 1.1x 10'. A 75 kg bobsled is pushed from rest horizontally. After travelling 4.5m its speed is 6m/s. Find the net force on the bobsled. 13. A 40kg child is in a swing attached to a 2m long rope. Find the gravitational PE of the child relative to her lowest point, when the ropes make an angle of 45° to the vertical 14. A spring with a spring constant of 5.2 N/m has a relaxed length of 2.45m. When a mass hangs vertically from the spring the stretched length is 3.57m. Find the elastic Potential Energy 15. The total Mechanical Energy of a system is defined as 16. A 25kg child zooms down a frictionless slide from an initial height of 3m. Find her speed at the bottom of the slide 17. A bird flies horizontally at 15m/s with a 2kg fish in its beak. The bird is 5m above the water when it accidentally drops the fish. Find the speed of the fish when it hits the water 18. An Olympic diver, 10m above the water, leaps upward with an initial speed of 3m/s. Find the divers speed upon hitting the water. 19. A2x 10 kg elevator must rise at a constant speed of 4m/s. A frictional force of 5000N will retard the motion of the elevator. What power must the motor deliver in order to lift the elevator in kW? 20. How long, in hours, will it take a 19kW steam engine to do 6.8 x 10 J of Work? 21. A motor driven winch pulls a 50kg student, 5m up at a constant speed of 1.25 m/s. How much Work is done by the motor? 22. A catcher "gives" with a baseball when catching it. If the baseball exerts a force of 475N on the glove such that the glove is displaced by 10cm, how much work is done on the ball? 23. A weightlifter holds a 100kg weight steady over his head. Is work being done against gravity? 24. A 0.5kg block on a vertical spring is compressed 100cm. When released, the block travels straight up. If the spring constant is 5.0 x 10 N/m, How high does the block rise above the point of release?

Answer 1

Power is a scalar quantity 1 hp is equal to 746 watts Transformed Displacement (because W = F^vector middot S^vector = FS cos theta) watt Joule negative