Recent content by PearlyD

Homework Statement A standing wave is set on a string by a vibrating the string at one end. You count 4 nodes on the standing wave. Which harmonic have you produced? The Attempt at a Solution I thought it was 3rd harmonic,but my teacher put 2nd harmonic whos right?

Im starting over again and I am spliting the question in two first one is the crouch,and I am going to find that force,that he uses to go from crouch to stand. But what kinematics equation would i use to find acceleration? I have Vi which is 0 and distance= 0.20 but that's it i don't know...

I used (mass)Gravity)(Displacement)=1/2mV^2 to get a velocity,would that work for this question?

Is 2a the same as displacement?

I now got it! THANK YOU SOOO MUCH! you do not know how much i appreciated you helping me through this! Thank you!

To find an initial velocity id either need a Final velocity or a time. and i don't have either.

thanks:) i got his velocity,but now i need the average force exerted on his torso by his legs during decelertation Would A =9.8? I thought it would go like this Fg-Ar=ma Where Fg=441 and mass= 45 and acceleration=9.8 but that just gives me a Air resistance of 1 and i don't think that's right

No, i haven't covered work. So from crouch to the point where his feet leave the ground i got a force of 129.36N How would you find the acceleration,to find the Force that he exerts againts the ground? the only equations i know of at the moment is Fnet=ma and Fg=mg

what does mgy mean?

What do you mean by work done? Also do you mean by this equation.. Work done* Displacement(0.2) EQUALS potential energy? and Potential energy is also 0.80*Gravity*mass?

Homework Statement A person jumps from the roof of a house 4.5m high. When he strikes the ground below, he bends his knees so that his torso decelerates over an approximate distance of 0.70m. This the mass of his torso(excluding legs) is 45Kg,find (a) his velocity just before his feet strike...

Homework Statement An Exceptional standing jump would raise a person 0.80m off the ground. To do this, what force must a 66Kg person exert against the ground? Assume the person crouches a distance of 0.20m prior to jumping, and thus the upward force has this distance to act over before he...

Homework Statement An exceptional standing jump would raise a person 0.80m off the ground. To do this, what force must a 66 kg person exert against the ground? Assume the person crouches a distance of 0.20 m prior to jumping,and thus the upward force has this distance to act over before he...

It must have!

No I am sure its that this question is straight from a textbook.