Question

15.
A body weight 4 N on the surface of the moon. So, its weight on the surface of the
earth is​

Answer 1

Given:-

• Weight of body on surface of moon Wₘ = 4N

To Find:-

• Weight of the surface of the earth ,Wₑ

Solution:-

As we know that weight of an body is defined as the product of mass and acceleration due to gravity.

The acceleration due to gravity on the Earth surface is 9.8m/s². and the acceleration due to gravity on the moon surface is 1/6 acceleration of the Earth's Surface .

It means that the acceleration due to gravity on the moon surface is

→ 1/6×9.8 = 1.63m/s²

g' = 1.63m/s²

Now , Calculating the mass of the body

• Wₘ = mg'

Substitute the value we get

→ 4 = m×1.63

→ m = 4/1.63

→ m = 2.5kg

Mass of the body is constant everywhere.So Weight of the body on the earth's surface is

•Wₑ = mg

Substitute the value we get

→ Wₑ = 2.5×9.8

→ Wₑ = 24.5N

∴ The weight of the body on the Earth's Surface is 24.5 Newton.

Answer 2

Answer:

Initial velocity ,u = 10m/s

Acceleration ,a = 8m/s²

Final velocity ,v = 40m/s

So By using 3rd equation of motion

• v² = u² +2as

Substitute the value we get

→ 40² = 10² +2×8×s

→ 1600 = 100 + 16×s

→ 1600-100 = 16×s

→ 1500 = 16×s

→ s = 1500/16

→ s = 93.75m

The length of Runway 93.80m