The value of g on the earth surface is 980 cm/sec2 . Its value at a height of 64 km from the earth surface is …………… cms–2
1) 960.40 2) 984.90 3) 982.45 4) 977.55 Answer: 1) 960.40 Solution: (g’/g) = [R/(R+h)]2 Given h = 64 km g... View Article
Latest Posts
A body weights 700 g wt on the surface of earth. How much it weight on the surface of planet whose mass is 1/7 and radius is half that of the earth
1) 200g ωt 2) 400g ωt 3) 50 g ωt 4) 300g ωt Answer: 2) 400g ωt Solution: g = GM/R2... View Article
A spherical planet far out in space has mas Mo and diameter Do. A particle of m falling near the surface of this planet will experience acceleration due to gravity which is equal to
1) GMo/Do2 2) 4mGMo/Do2 3) 4GMo/Do2 4) GmMo/Do2 Answer: 3) 4GMo/Do2 Solution: Acceleration due to gravity, g = GM0/R2 Radius R... View Article
The time period of a simple pendulum on a freely moving artificial satellite is …………… sec
1) 0 2) 2 3) 3 4) Infinite Answer: 4) Infinite Solution: Time period, T = 2π√l/g’ In artificial satellite, g’... View Article
The radius of the earth is 6400 km and g=10ms-2. In order that a body of 5 kg weights zero at the equator, the angular speed of the earth is = …………… rad/sec
1) 1/80 2) 1/400 3) 1/800 4) 1/600 Answer: 3) 1/800 Solution: Due to the rotation of earth at the equator... View Article
If R is the radius of the earth and g is the acceleration due to gravity on the earth’s surface, the mean density of the earth is = ……………
1) 4πG/3gR 2) 3πR/4gG 3) 3g/4πRG 4) πRG/12g Answer: g = GM/R2 Mass, M = Volume x Density M =... View Article
As we go from the equator to the poles, the value of g ……………
1) Remains constant 2) Decreases 3) Increases 4) Decreases up to the latitude of 45o Answer: 3) Increases The shape of... View Article
The time period of a satellite of earth is 5 hours. If the separation between the earth and the satellite is increased to 4 times the previous value, the new time period will become
1) 40 hours 2) 20 hours 3) 10 hours 4) 80 hours Answer: 1) 40 hours Solution: T2 ∝ R3 ⇒ (T1/T2)... View Article
To an astronaut in a spaceship, the sky appears to pitch dark because of
1) the absence of atmosphere in his neighbourhood. 2) light from the sky is absorbed by the medium surrounding him.... View Article
If suddenly the gravitational force of attraction between the earth and a satellite revolving around it becomes zero, then the satellite will
1) continue to move in its orbit with the same velocity 2) move tangentially to the original orbit with the... View Article
Astronaut is in a stable orbit around the earth when he weighs a body of mass 5 kg. What is the reading of spring balance?
1) Spring will not be extended 2) Spring will be extended according to Hooke’s law 3) Less than 5 kg-wt... View Article
A satellite is launched in a circular orbit of radius R around the earth. A second satellite is launched into an orbit of radius 1.01 R. The period of the second satellite is longer than the first one (approximately) by
1) 1.5% 2) 0.5% 3) 3% 4) 1% 5) 2% Answer: 1) 1.5% Solution: Since, T ∝ R3/2 T1 ∝ R3/2 T2 ∝... View Article
The time period of a satellite of the earth is 5 h. If the separation between the earth and the satellite is increased to 4 times the previous value, the new time period will become
1) 10 h 2) 80 h 3) 40 h 4) 20 h Answer: 3) 40 h Solution: Since T ∝ R3/2... View Article
Three weights w, 2w and 3w are connected to identical spring suspended from a rigid horizontal rod. The assembly of the rod and the weights fall freely. The positions of the weight from the rod are such that
1) 3w will be farthest 2) w will be farthest 3) all will be at the same distance 4) 2w... View Article
Kepler’s second law states that the straight line joining the planet to the sun sweeps out equal areas in equal times. This statement is equivalent to saying that
1) total acceleration is zero 2) tangential acceleration is zero 3) longitudinal acceleration is zero 4) radial acceleration is zero... View Article
Acceleration due to gravity is g on the surface of the earth. Then, the value of the acceleration due to gravity at a height of 32 km above earth’s surface is (assume radius of earth to be 6400 km)
1) 0.99 g 2) 0.8 g 3) 1.01 g 4) 0.9 g Answer: 1) 0.99 g Solution: For the height h... View Article
The acceleration due to gravity on planet A is 9 times the acceleration due to gravity on planet B. A man jumps to a height of 2 m on the surface of A. What is the height of the jump by the same person on planet B?
1) 6 m 2) 2/3 m 3) 2/9 m 4) 18 m Answer: 4) 18 m Solution: The acceleration due to... View Article
A body is orbiting around the earth at a mean radius which is two times as greater as the parking orbit of a satellite, the period of body is
1) 4 days 2) 16 days 3) 2√2 days 4) 64 days Answer: 3) 2√2 days Solution: According to Kepler’s third... View Article
A satellite in a circular orbit of radius R has a period of 4 h. Another satellite with orbital radius 3R around the same planet will have a period (in hour)
1) 16 2) 4 3) 4√27 4) 4√8 Answer: 3) 4√27 Solution: According to Kepler’s third law T2 ∝ R3 \(\begin{array}{l}\Rightarrow \frac{T_{2}}{T_{1}}=(\frac{R_{2}}{R_{1}})^{3/2}\end{array}... View Article
A satellite is revolving around the earth with a kinetic energy E. The minimum addition of kinetic energy needed to make its escape from its orbit is
1) 2E 2) √E 3) E/2 4) √E/2 5) E Answer: 5) E Solution: Orbital velocity of the satellite \(\begin{array}{l}V_{o}= \sqrt{\frac{GM}{r}}\end{array} \) Kinetic... View Article
