Question:
Fill in the blanks :
The value of g on the earth's surface is ______.
Gravitation
Q 1.
State Kepler’s Laws of planetary motion. How did Newton guess inverse square law ?
Q 2.
A particle is dropped from a tower 180 m high.How long does it take to reach the ground ? What is the velocity when it touches the ground ? Take g =
Q 3.
Why do sewing needles and all pins have a sharp pointed tip?
Q 4.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 5.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 6.
A boy on a clif£ 49 m high drops a stone.One second later,he throws a second stone after the first.They both hit the ground at the same time. With what speed did he throw the second stone ?
Q 7.
Suppose a planet exists whose mass and radius both,are half those of Earth.Calculate the acceleration due to gravity on the surface of this planet.
Q 8.
Which force is responsible for tides in the ocean at night ?
Q 9.
Two stones A and B are dropped from a multistoried building. A is dropped from 100 m and after some time B is dropped from 50 m height. Both of them reach the earth at the same time. Will they have equal velocity while reaching the ground ? Calculate and find out the answer (take g =10 m/s
2).
Q 10.
At what height above the surface of the earth, the value of 'g' becomes 64% of its value at the surface of the earth. Take radius of the earth = 6400 km.
Q 11.
What is the value of ‘g’ at the centre of Earth ?
Q 12.
What do we call the gravitational force between the Earth and an object ?
Q 13.
What do you mean by acceleration due to gravity ?
Q 14.
Calculate the force of gravitation between the Earth and the Sun,given that the mass of the Earth =
kg and mass of the Sun =
kg. The average distance between the two is
m.
Q 15.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 16.
The mass of Earth is
kg and that of moon is
kg. If the distance between the Earth and the Moon is
km, calculate the force exerted by Earth on the Moon. Given G =
.
Q 17.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 18.
Who measured the value of G first time, experimentally?
Q 19.
Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth = 6 × 10
24 kg and of the Sun = 2 × 10
30 kg. The average distance between the two is 1.5 × 10
11 m.
Q 20.
Calculate the force of gravitation between two objects of masses 80 kg and 1200 kg kept at a distance of 10 m from eachother.Given, G =
/
.
Q 21.
Write the standard equations of motion when an object is thrown upwards with some initial velocity?
Q 22.
What is the importance of universal law of gravitation ?
Q 23.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 24.
What is the gravitational acceleration of a spaceship at a distance equal to two Earth’s radius from the centre of the Earth ?
Q 25.
Fill in the blanks :
The value of
g at poles is ______ (lower/higher) than its value at the equator.
Q 27.
Fill in the blanks :
Assuming negligible air drag, if a steel ball and a table tennis ball are dropped from a height of 100 metres, both will reach the ground at ________ time(s). (same/different)
Q 28.
What was geocentric model? Who proposed this theory?
Q 29.
What happens to 'g' experienced by a body when it moves up the earth's surface?
Q 31.
Fill in the blanks :
The gravitational force between the earth and the object is generally called ____________.
Q 32.
A stone is allowed to fall from the top of a tower 100 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25 m/s. Calculate when and where the two stones will meet
Q 33.
Fill in the blanks :
Heliocentric model was proposed by ______.
Q 34.
Fill in the blanks :
Weight of an object is the product of ______ and ________.
Q 35.
Fill in the blanks :
The force of gravity _________ with altitude. It also varies on the surface of the earth, _________ from poles to the equator.
Q 36.
A force of 20 N acts upon a body whose weight is 9.8 N.What is the mass of the body and how much is its acceleration ?
Q 37.
What do you mean by free fall ?
Q 38.
Which force accelerates a body in free fall ?
Q 39.
Who explained the motion of planets around the Sun ?
Q 40.
Can you calculate mass of Earth from Newton’s law of gravitation ?
Q 41.
Fill in the blanks :
Kepler's Law of ______ states that a line that connects a planet to the Sun sweeps out equal ______ in the plane of the planet's orbit in _____time intervals.
Q 42.
(a) What is the relationship between g and G?
(b) Show mathematically whether g (acceleration due to gravity on the earth) depends on the mass of the object itself or not.
(c) Show that for a given location on the surface of the earth g is almost constant.
Q 43.
Define weight? How it is related to mass?
Q 44.
A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate(i) the maximum height to which it rises.(ii)the total time it takes to return to the surface of the earth.
Q 45.
A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity just before touching the ground.
Q 46.
The volume of 50 g of a substance is 20 cm
3. If the density of water is 1 g cm
-3, will the substance float or sink?
Q 47.
A car falls off a ledge and drops to the ground in 0.5 s.Let g =
(for simplifying the calculations).
(i) What is its speed on striking the ground ?
(ii) What is its average speed during 0.5 s ?
(iii) How high is the ledge from the ground ?
Q 48.
State the universal law of gravitation.
Q 49.
Does Newton’s third law of motion apply to gravitational force ?
Q 50.
Where is ‘g' maximum, on the surface of Earth, above the surface or below the surface of Earth ?
