Gravitation · Question 15

A satellite of mass 1000 kg is launched to revolve around the earth in an orbit at a height of 270 km from the earth's surface. Kinetic energy of the satellite in this orbit is 1010 J. (Mass of earth = 6 1024 kg, Radius of earth = 6.4 106 m, Gravitational constant = 6.67 10-11 N m2 kg-2)

Answer

3

Solution

Orbital radius: r = R + h = 6.4 106 + 0.27 106 = 6.67 106 m

For a circular orbit mv2r = GMmr2 KE = GMm2r

KE = 6.67 10-11 6 1024 10002 6.67 106

= 3 1010 J

Answer: 3