For all you smarties, i need help with PHYSICS Options

[mmmchocolate]

Alright i SUCK at physics and need some help with a few problems concerning work-energy-momentum, im working through a worksheet and will be posting more problems as i get to them. but for now here is one i seem to be stuck on, don't make fun of my stupidness if this seems easy to some of you.
BTW my teacher write his own problems so thats why the questions are a little different

Jake "the Big-Man" Wickstrom rolls a double-wide old-school Toro Lawnmower across Mrs. Omalley's lawn with a force of 300N in the direction of the stainless steel handle, which forms an agle of 34.0 degrees with the ground (is at an angle of 34.0 degrees above the horizon).
A) If Jake produces 150Watts of power for 90.0 seconds, what distance is the mower pushed in meters and in feet?
B) How much horespower does Jake "the Big-Man" Wickstrom produce?

[lagos]

The question kind of makes no sense. Jake is a person, and he produces 150watts?
Only thing I can make out is that you have a velocity of 300nm because you have acceleration and direction, and I dont see how the angle of the handle would make any difference .

This post has been edited by lagos: Feb 17, 2009 - 8:37 PM

[mmmchocolate]

ok i solved A. Jake went 54.28m, 178.08ft, now onto B....

[azian_advanced]

part B should be simple enough, just convert 150 watts into HP. i don't remember the conversion factor off the top of my head but it's something like 1.36 HP = 1 KW = 1000 watts.

for part a i got 45cos35 meters which is less than what u got. i could be wrong though.

[mmmchocolate]

well if you use the formula p=(F)(D)/(T) so P=(248.711271j)(54.28m)/(90s) it adds back to 150w so that works out, and then i just divided 150/550ftlb/s i get .27 hp, which when i type in 150w into horsepower in google it comes out with .2 so its close enough... but im pretty sure im right...not 100% though

[azian_advanced]

oic what u did. yeah i think you're right.

[mmmchocolate]

NEW----
Katerina, a 60-kg dancer from Moscow, Russia, leaps 0.32 m high.
A. With what momentum does katerina reach the ground?
B. What impulse is needed to make Katerina stop?
C. As katerina lands, her knees bend 0.12 m, lengthening the time required to stop to 0.05s. Find the average force exerted on her body?

[azian_advanced]

no offense, but it sounds like you want us to do your homework for you

[mmmchocolate]

well thats exactly what im asking im no good at physics and i need an A so

[Consynx]

NEW----
Katerina, a 60-kg dancer from Moscow, Russia, leaps 0.32 m high.
A. With what momentum does katerina reach the ground?
B. What impulse is needed to make Katerina stop?
C. As katerina lands, her knees bend 0.12 m, lengthening the time required to stop to 0.05s. Find the average force exerted on her body?

A)
Energy Balance ==> mgh = 1/2mv^2 ==> 60*9.81*0.32 *2 /60 = v^2 Solve for v, then multiple by m for a "momentum"...at least i'm assuming that's what your teacher wants. kg*m/s for a unit??? lol
B)
No Clue, It sounds like it needs a time value... the old F*t=mv type of equation...in which case this might be an attempt at a trick, and the answer is the same as A.
C)
same equation, or so i'd think. So F*0.05 = 60*(v from part A)

learn to do physics, especially if your major involves lots of math.

[soulshadow]

lmao this is my homework for next week. Maybe if u finish first u can help me later.

[mmmchocolate]

ha, actually i did pretty good on the assignment, i got an 83%. which is pretty good compared to how "smart" my friends are. i mean this one friend i have never studies, never does his homework and he has A's and gets amazing grades on tests. pisses me off, i do my homework, study hard, and end up with the A occasional B. i actually got a higher grade on this physics assignment than my friend, so i was pleased! HA. buy yeah ask you question and i can probably give you some sweet examples.

-i realized that you posted a week ago, so you are probably done. oh well

This post has been edited by mmmchocolate: Feb 27, 2009 - 1:33 PM