applesjgtl
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?
Delete
Share
This Question is Closed
applesjgtl
Best Response
You've already chosen the best response.
0
W=f*d?
Shane_B
Best Response
You've already chosen the best response.
1
Let me restate that...calculate the PE :)
applesjgtl
Best Response
You've already chosen the best response.
0
Oh, okay. \[PE=mg \Delta y\]?
Shane_B
Best Response
You've already chosen the best response.
1
Yes \[\Delta PE = mg\Delta h\]
applesjgtl
Best Response
You've already chosen the best response.
0
Okay: \[(750g)(9.81m/s^2)(15m)=110,362.5J\]
Shane_B
Best Response
You've already chosen the best response.
1
Almost...your mass needs to be in kg. Anyway, you'll get 110.3625J
applesjgtl
Best Response
You've already chosen the best response.
0
So the mass would be 7.5 kg?
Shane_B
Best Response
You've already chosen the best response.
1
No :) 750g = 0.75kg
applesjgtl
Best Response
You've already chosen the best response.
0
Sorry, what is s?
Shane_B
Best Response
You've already chosen the best response.
1
seconds
Shane_B
Best Response
You've already chosen the best response.
1
\[Watts=\frac{Joules}{second}\]
applesjgtl
Best Response
You've already chosen the best response.
0
and that would be equal to 330W
Shane_B
Best Response
You've already chosen the best response.
1
To be more clear:\[330W=\frac{330Joules}{second}\]
applesjgtl
Best Response
You've already chosen the best response.
0
Hm. That can't be right, can it? Perhaps: \[330W=110.3625J/time (s)\]
Shane_B
Best Response
You've already chosen the best response.
1
That's not what I'm saying :) I just showed the conversion of 330W to Joules/second
applesjgtl
Best Response
You've already chosen the best response.
0
Oh right, I guess I knew that.
Shane_B
Best Response
You've already chosen the best response.
1
So if you have 330J/s of power available and need to perform 110.3625J of work, how long would that take?
applesjgtl
Best Response
You've already chosen the best response.
0
36419.63 seconds?
applesjgtl
Best Response
You've already chosen the best response.
0
That seems really long.
applesjgtl
Best Response
You've already chosen the best response.
0
Also seems wrong.
Shane_B
Best Response
You've already chosen the best response.
1
It is. So your intuition is correct...that's not the answer
Shane_B
Best Response
You've already chosen the best response.
1
\[\frac{110.3625J}{330J/s}=?\]
Shane_B
Best Response
You've already chosen the best response.
1
It will take about 1/3 of a second :)
applesjgtl
Best Response
You've already chosen the best response.
0
I got .3344 seconds. Don't know how I got so confused the first time around. Thanks for your help, Shane!
Shane_B
Best Response
You've already chosen the best response.
1
no problem. I get confused sometimes too...it's physics after all!