Question

A helicopter is hovering at an altitude of 1km when a panel from its underside breaks loose and plummets to the ground. The mass of the panel is 15kg and it its the ground with a speed of 45m/s. How much mechanical energy was dissipated by air resistance during the panel’s descent?

Answer 1

The right answer is "131812.5".

Step-by-step explanation:

The given values are:

Mass,

m = 15 kg

Velocity,

v = 45 m/s

As we know,

⇒
`PE_1=mgh`

On putting the values, we get

⇒
`=15* 9.8* 1000`

⇒
`=147000 \ J`

According to the question,

`KE_1=0 \ J`

`PE_f=0 \ J`

⇒
`KE_f=(1)/(2)* 15* 45^2`

⇒
`=(1)/(2)* 15* 2025`

⇒
`=15187.5 \ J`

hence,

⇒
`PE_i=KE_f+W_(air)`

or,

⇒
`W_(air) = PE_i-KE_f`

⇒
`=147000-15137.5`

⇒
`=131812.5 \ J`