Question

Lora (of mass 54 kg) is an expert skier. She

starts at 2.6 m/s at the top of the lynx run,
which is 51 m above the bottom.
What is her final kinetic energy at the bottom of the ski run?

Answer 1

The mechanical energy at top =Mechanical energy at bottom

• Mass=m=54kg
• Height=h=51m
• Acceleration due to gravity=g=10m/s^2
• Velocity=v=2.6m/s

`\\ \tt\longmapsto M_(initial)=M_(Final)`

• Final energy at bottom=The kinetic energy

`\\ \tt\longmapsto KE=M_(initial)`

`\\ \tt\longmapsto KE=P.E_((Top))+K.E_((Top))`

`\\ \tt\longmapsto K.E=mgh+(1)/(2)mv^2`

`\\ \tt\longmapsto K.E=m\left(gh+(v^2)/(2)\right)`

`\\ \tt\longmapsto K.E=54\left((10)(51)+(2.6^2)/(2)\right)`

`\\ \tt\longmapsto K.E=54\left(510+(6.76)/(2)\right)`

`\\ \tt\longmapsto K .E=54(510+3.38)`

`\\ \tt\longmapsto K.E=54(513.38)`

`\\ \tt\longmapsto K.E=27722.52J`

`\\ \tt\longmapsto K.E=27.7KJ`