An object with a massof 100 grams (0.100 kg) is dropped from a certain height and has a velocity of 60 meters/second. If the potential energy of this object is 179.99 joules, how high was the object when it was dropped?

a) 9.2 x 10^1 meters.
b) 1.8 x 10^2 meters.
c) 9.8 x 10^2 meters.
d) 1.0 x 10^2 meters.

Question

An object with a massof 100 grams (0.100 kg) is dropped from a certain height and has a velocity of 60 meters/second. If the potential energy of this object is 179.99 joules, how high was the object when it was dropped?

a) 9.2 x 10^1 meters.
b) 1.8 x 10^2 meters.
c) 9.8 x 10^2 meters.
d) 1.0 x 10^2 meters.

ivancsc1996 · Answer

So when the speed is 60m/s the potential energy was transformed into kinetic energy. This means:$$\frac{ 1 }{ 2 }mv ^{2}=mgh=PE=KE$$If you solve for h you get this which then you need to evaluate to get the answer:$$h=\frac{ v ^{2} }{ 2g }$$