Question

Question 55:
The mass of a planet is 6 x 1024 kg and its diameter is 12.8 x 103 If the value of gravitational constant be 6.7 x 10-11 Nm2/kg2, calculate the value of acceleration due to gravity on the surface of the planet. What planet could this be ?

Lakhmir Singh Physics Class 9

Answer 1

Answer:

A planet has a mass of 6×10^24 kgs.

It has a diameter of 12.8 ×10^3 km or 12.8 ×10^6m.

So according to the problem we have to find out the acceleration due to gravity of that planet.

Now, we know that gravitational value is constant, so it is 6.7×10^-11 Nm^2/Kg^2.

The formula to find acceleration due to gravity is :

g= G × (M/R^2)

Where g is the acceleration due to gravity, G is the gravitational constant M is the mass and R is the radius.

To find radius, we have to divide the diameter with 2.

So R will be (12.8×10^6/2)m

= 6.4 × 10^6 m.

So,

g= 6.7× 10^-11 × [6×10^24/(6.4 × 10^6)^2]

= 6.7 × 60/ 6.4× 6.4

= 9.8m/s^2

The planet is Earth as its acceleration due to gravity is 9.8m/s^2.