The escape velocity of a body on the surface of the earth is 11.2 km/s. If the earth's mass increases to twice its present value and the radius of the earth becomes half, the escape velocity would become
44.8 km/s
22.4 km/s
11.2 km/s (remain unchanged)
5.6 km/s
A satellite A of mass m is at a distance r from the surface of the earth. Another satellite B of mass 2m is at a distance of 2r from the earth's surface. Their time periods are in the ratio of
1 : 2
1 : 16
1 : 32
1 : 2 √2
The figure shows elliptical orbit of a planet m about the sun S. The shaded area SCD is twice the shaded area SAB. If t1 is the time for the planet to move from C to D and t2 is the time to move from A to B, then
t1 > t2
t1 = 4t2
t1 = 2t2
t1 = t2
The earth is assumed to be a sphere of radius R. A platform is arranged at a height R from the surface of the earth. The escape velocity of a body from this platform is fve , where ve is its escape velocity from the surface of the earth. The velocity of f is
For a satellite escape velocity is 11 km/s. If the satellite is launched at an angle of 60o with the vertical, then escape velocity will be
11 km/s
33 km/s
The mean radius of earth is R, its angular speed on its own axis is ω and the acceleration due to gravity at earth's surface is g. What will be the radius of the orbit of a geostationary satellite?
A planet is moving in elliptical orbit around the sun. If T, U, E and L stand for its kinetic energy, gravitational potential energy, total energy and magnitude of angular momentum about the centre of force, which of the following is correct?
T is conserved.
U is always positive.
E is always negative.
L is conserved but direction of vector L changes continuously.
A rubber ball is dropped from a height of 5 m on a planet where the acceleration due to gravity is not known. On bouncing it rises to 1.8 m. The ball loses its velocity on bouncing by a factor of
16/25
2/5
3/5
9/25
A roller coaster is designed such that riders experience "weightlessness" as they go round the top of a hill whose radius of curvature is 20 m. The speed of the car at the top of the hill is between
14 m/s and 15 m/s
15 m/s and 16 m/s
16 m/s and 17 m/s
13 m/s and 14 m/s
If the gravitational force between two objects were proportional to 1/R (and not as 1/R2), where R is separation between them, then a particle in circular orbit under such a force would have its orbital speed v proportional to
1/R2
Ro
R
1/R
