A monkey uses a fishing pole to raise 750g of bananas up to his position 15m above the ground. If the monkey's power output was 330 W, how long did it take to reel in the bananas?

Question

anonymous · Answer

W=f*d?

shane_b · Answer

Let me restate that...calculate the PE :)

anonymous · Answer

Oh, okay. $$PE=mg \Delta y$$?

shane_b · Answer

Yes $$\Delta PE =  mg\Delta h$$

anonymous · Answer

Okay: $$(750g)(9.81m/s^2)(15m)=110,362.5J$$

shane_b · Answer

Almost...your mass needs to be in kg.  Anyway, you'll get 110.3625J

anonymous · Answer

So the mass would be 7.5 kg?

shane_b · Answer

No :)  750g = 0.75kg

anonymous · Answer

Sorry, what is s?

shane_b · Answer

seconds

shane_b · Answer

$$Watts=\frac{Joules}{second}$$

anonymous · Answer

and that would be equal to 330W

shane_b · Answer

To be more clear:$$330W=\frac{330Joules}{second}$$

anonymous · Answer

Hm. That can't be right, can it? Perhaps: $$330W=110.3625J/time (s)$$

shane_b · Answer

That's not what I'm saying :)  I just showed the conversion of 330W to Joules/second

anonymous · Answer

Oh right, I guess I knew that.

shane_b · Answer

So if you have 330J/s of power available and need to perform 110.3625J of work, how long would that take?

anonymous · Answer

36419.63 seconds?

anonymous · Answer

That seems really long.

anonymous · Answer

Also seems wrong.

shane_b · Answer

It is.  So your intuition is correct...that's not the answer

shane_b · Answer

$$\frac{110.3625J}{330J/s}=?$$

shane_b · Answer

It will take about 1/3 of a second :)

anonymous · Answer

I got .3344 seconds. Don't know how I got so confused the first time around. Thanks for your help, Shane!

shane_b · Answer

no problem.  I get confused sometimes too...it's physics after all!