Question

A model rocket with a mass of 0.212 kg is launched into the air with an initial speed of 84 m/s. How much kinetic energy will the rocket have at a height of 214 m? Assume there is no wind resistance.

444 J

747 J

303 J

634 J

Answer 1

Option C

303 J

Step-by-step explanation:

Energy can neither be created nor destroyed but only transformed from one state to the other.

Initial
`KE=0.5mv^(2)=0.5*0.212*84^(2)=747.936 J`

Initial potential energy=mgh but since h=0 then energy is 0

Final potential energy=mgh=0.212*9.81*214=445.06008 J

Considering that initial energy is 747.936+0=747.936 J, final energy should also be the same. The final kinetic energy is the difference between total sum of energy and potential energy

`KE=747.936-445.06008=302.87592\approx 303 J`