Question

Find the KE of 40,000 kg airplane moving at 80 m/s at 2000 meters above the ground.

Answer 1

The kinetic energy of the airplane is
`128* 10^6\ J`

Step-by-step explanation:

Given:

Mass of the airplane is,
`m=40000\ kg`

Velocity of the airplane is,
`v=80\ m/s`

Height of airplane is,
`H=2000\ m`

Kinetic energy of a body is independent of the height and only depends on its velocity.

Kinetic energy of a body of mass 'm' and moving with a velocity 'v' is given as:

`KE=(1)/(2)mv^2`

Where
`KE\to Kinetic\ energy`

Now, plug in 40000 kg for 'm', 80 m/s for 'v' and solve for 'KE'. This gives,

`KE=(1)/(2)* (40000\ kg)* (80\ m/s)^2\\\\KE=20000* 6400\ kg\cdot m^2/s^2\\\\KE=128* 10^6\ J.....[1\ J=1\ kg\cdot m^2/s^2]`

Therefore, the kinetic energy of the airplane is
`128* 10^6\ J`