An object is dropped from rest from a height of 4.4 107 m above the surface of the Earth. If there is no air resistance, what is its speed when it strikes the Earth?

Explanation:

An object is drop from a height, then it is in direction of gravity

g is +ve

When an object drop from a height, the initial velocity is 0,

U=0

Given that h=4.4×10^7m

V=?

g=9.81m/s^2

Then using equation of motion

V^2=U^2+2gh

V^2=0+2×9.81×4.4×10^7

V^2=86.33×10^7m/s

Take square root of both side

V=29381.63m/s

Now to km/s, divide by 1000

Since 1km=1000m

V=29.38km/s