a)Water is at rest at the bottom of a well of depth h = 2.95 m. A pump lifts mas

Question

a)Water is at rest at the bottom of a well of depth h = 2.95 m. A pump lifts mass at a rate of dm/dt = 138 kg/minute from the well and ejects it with a speed v = 5.67. m/s. If there is no friction anywhere, find P, the power (energy per time) needed to do this work.
2 W

b) A projectile of mass m = 7.98 kg is fired straight upward twice, both times at initial speed vo = 68.2 m/s. The first time there is no air friction, and the projectile reaches height ho; the second time the air dissipates Elost = 4435 J of energy as the projectile rises, and it rises to height h. Find ho - h, the difference betwen the height the projectile reaches without friction and the height it reaches with friction.
3 m

c) A one-dimensional force acts on a particle of mass m = 2.06 kg in such a way that its position is given by:

Find W, the work done by this force during the first 4.95 s.

Explanation / Answer

rate of water lifted=2.3kg/s

Change in potential energy of water/s=mgh

Change in kinetic energy=0.5mv2

Total change in energy=mgh+0.5mv2=103.5W

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