Question

A boulder rests on a ledge 31.2 m above a lake. If it has 2.65 × 105 J of gravitational potential energy relative to the lake surface, what is the mass of the boulder?

Answer 1

Using the equations for potential and kinetic energy, we can solve for the height of the hill.

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.gh=12v2

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.gh=12v2(−9.8ms2)h=12(12ms)2

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.gh=12v2(−9.8ms2)h=12(12ms)2(−9.8ms2)h=12144m2s2

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.gh=12v2(−9.8ms2)h=12(12ms)2(−9.8ms2)h=12144m2s2(−9.8ms2)h=72m2s2

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.gh=12v2(−9.8ms2)h=12(12ms)2(−9.8ms2)h=12144m2s2(−9.8ms2)h=72m2s2h=72m2s2−9.8ms2

Using the equations for potential and kinetic energy, we can solve for the height of the hill.mgh=12mv2The masses cancel, and we can plug in our final velocity and gravitational acceleration.gh=12v2(−9.8ms2)h=12(12ms)2(−9.8ms2)h=12144m2s2(−9.8ms2)h=72m2s2h=72m2s2−9.8ms2h=−7.35m