I have two questions regarding this, any help would be GREAT!(adsbygoogle = window.adsbygoogle || []).push({});

1st Problem:

1. The problem statement, all variables and given/known data

A conveyor belt lifts 1000kg of rocks per minute a vertical distance of 10m. The rocks are at rest at the bottom of the belt and are ejected at 5 m/s. The power supplied to this machine is:

A) 1000W

B) 1260W

C) 1630W

D) 1840W

E) 2100 W

2. Relevant equations

P=Fv

p=mv

[tex]\sum[/tex]F[tex]\Delta[/tex]T=m(vf-vo)

3. The attempt at a solution

vo = 0m/s

vf = 5m/s

1000kg/min = 16.67kg/s

sumF[tex]\Delta[/tex]T=m(vf-vo)

sumF=m(vf-vo)/[tex]\Delta[/tex]T

sumF=m(vf)-m(vo)/[tex]\Delta[/tex]T

since vo = 0/ms

sumF=m(vf)/[tex]\Delta[/tex]T

sumF=m/[tex]\Delta[/tex]T (vf)

subbing in values...

m/dT = 16.67kg/s

F = (16.67)(5) = 83.35N

and now for Power...

P = Fv

P = 83.35(5) = 416.75W

Now, I know i've done something wrong, especially as I haven't accounted for height. I feel like I am EXTREMELY off with attempting to solve this so i'd appreciate any help.

2nd Problem:

1. The problem statement, all variables and given/known data

Water runs out of a horizontal pipe at the rate of 120kg/min. It falls 3.20m to the ground. Assuming the water doesn't splash up, what average vertical force does it exert on the ground?

2. Relevant equations

P=Fv

p=mv

sumF[tex]\Delta[/tex]T=m(vf-vo)

3. The attempt at a solution

SOLVED THIS ONE - if anyone else needs the solution though let me know and i'll post it.

Still need help on the first though... workin' on it however.

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# Homework Help: Impulse and Momentum Q!

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