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physicsss
Oct12-04, 03:03 AM
If you stand on a bathroom scale, the spring inside the scale compresses 0.50 mm, and it tells you your weight is 805 N. Now if you jump on the scale from a height of 2.0 m, what does the scale read at its peak?

I used F=kx, and solved for k...but I don't know what to do after that...do I set

mgh=kx, where m is 805/9.8 and h is 2.0m?

Galileo
Oct12-04, 05:01 AM
I used F=kx, and solved for k...but I don't know what to do after that...do I set

mgh=kx, where m is 805/9.8 and h is 2.0m?

The idea is correct.
At the point where the spring is compressed the most, all gravitational potential energy has been converted to potential energy in the spring.

However, the energy stored in the spring is not kx.

physicsss
Oct12-04, 07:10 PM
mgh=1/2kx^2?

Pyrrhus
Oct12-04, 07:17 PM
Yes, physicss