Gravitation 2 class 9

The SI unit of G

• Ncm²/kg²

• Nm²kg²

• Nm²/kg²

• Nkg/m²

What is the gravitational force between two objects?

• attraction at large distance only

• attraction at small distance only

• attraction at all distances

• attraction at large distances but repulsive at small distances

The earth attracts the moon with a gravitational force of 10²² N.The moon attracts the earth with a gravitational force of

• less than 10²² N

• 10²² N

• Greater than 10²² N

• 10-²² N

A stone is released from the top of the tower with height 81.64 m.Calculate its final velocity before touching the ground.

• 90m/s

• 60m/s

• 40m/s

• 50m/s

The gravitational force between two objects is F. Determine the new Force on halving the masses of both the objects.

• F/4

• 2F

• F/2

• 4F

Two bodies, held 2m vertically above each other are released together and fall freely. After 4s how far will they be?

• 19.6 m

• 1 m

• 4.9 m

• 2 m

A boy drops a ball from a tower 49 m high, how long does it take for the ball to fall to the ground?

• 5 secs

• √10 = 3.16 secs

• 10 secs

• 1 sec

In first 4 secs it will travel ___________ m.

(refer to Q7.)

Isaac Newton's universal law of gravitation

• showed how one law could explain all motion in the universe

• was denounced by the Anglican Church as work of the Devil

• was laughed at by Galileo, Kepler, & Copernicus

• refuted Galileo Galilei's theory of universal movement

Calculate the gravitational force between a 15-kg chinchilla and a 65-kg dog which are separated by 0.30 m.

• 3.7*10^-8 N

• 1.3*10¹² N

• 1.1*10⁵ N

• 7.2*10^-7 N