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A 66kg trampoline artist hits a trampoline with a velocity of 7.5m/s. If the trampoline acts as a spring with constant 6.5*10^4N/m, what is the distance he depresses the trampoline.

My reasoning:
Calculate KE=1/2mv^2=1856.25J
KE=W=Fd
F=kx
x=d (not sure of this)
==>KE=kx^2
1856.25=(6.5*10^4)*x^2
x=0.17m

Says it's wrong. Probably because x=/=d or KE=/=Fd.

September 26, 2013

2 Comments • Newest first

Al3xL3g3nd

[quote=HolyDragon]Here's my guess.

The total energy of the gymnist at that time is all Kinetic energy (1856.25J)
That's the energy applied on the trampoline.

Spring energy formula
PE=1/2k x^2
sub it in and it should work.[/quote]
It worked. Thanks

Reply September 26, 2013
HolyDragon

Here's my guess.

The total energy of the gymnist at that time is all Kinetic energy (1856.25J)
That's the energy applied on the trampoline.

Spring energy formula
PE=1/2k x^2
sub it in and it should work.

Reply September 26, 2013 - edited