Question:
What do you mean by acceleration due to gravity ?
Answer:
In free fall, there is no change in the direction of motion of objects.But the magnitude of velocity of falling objects goes on increasing.It means acceleration is produced in a body in free fall.This acceleration is called acceleration due to gravity.We may define acceleration due to gravity as the acceleration produced in a body in free fall due to gravitational force of Earth on the body.
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.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 4.
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 5.
Why do sewing needles and all pins have a sharp pointed tip?
Q 6.
What is the value of ‘g’ at the centre of Earth ?
Q 7.
Which force is responsible for tides in the ocean at night ?
Q 8.
Fill in the blanks :
Every object in the universe ________ other bodies.
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.
What do you mean by acceleration due to gravity ?
Q 11.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 12.
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 13.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 14.
Who measured the value of G first time, experimentally?
Q 15.
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 16.
What is the importance of universal law of gravitation ?
Q 17.
What do we call the gravitational force between the Earth and an object ?
Q 18.
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 19.
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 20.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 21.
Does the force of attraction between two objects depend on the properties of intervening medium?
Q 22.
What are the differences between the mass of an object and its weight?
Q 23.
Why will a sheet of paper fall slower than one that is crumpled into a ball?
Q 24.
Two bodies A and B having masses 2 kg and 4 kg respectively are separated by 2 m.Where should a body of mass 1 kg be placed so that the gravitational force on this body due to bodies A and B is zero ?
Q 25.
State the universal law of gravitation.
Q 26.
What is the acceleration of free fall ?
Q 27.
Who explained the motion of planets around the Sun ?
Q 28.
Does value of ‘g’ vary from place to place on Earth ?
Q 29.
What is the weight of a body of mass 1 kg on Earth ?
Q 30.
A body weighs 10 kg on the surface of earth.What would be its mass and weight at the centre of earth ?
Q 31.
Fill in the blanks :
The force which keeps the object moving in a circular path is called _____ force. It always acts towards the _____.
Q 32.
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 33.
Fill in the blanks :
The value of Universal Gravitation constant (G) is ________ Nm
2kgs
-2.
Q 34.
Fill in the blanks :
Weight of an object is the product of ______ and ________.
Q 35.
Why is G called the Universal Constant?
Q 36.
What is the gravitational force between the Earth and a body called? In which direction does it occur?
Q 37.
How does value of 'g' vary on the earth? What are the factors responsible for this?
Q 38.
What happens to 'g' experienced by a body when it moves up the earth's surface?
Q 39.
A stone is thrown vertically upward with an initial velocity of 40 m/s. Taking g = 10 m/s
2, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?
Q 41.
Why does one feel giddy while moving on a merry go round ?
Q 42.
The tangential velocity of a planet or moon moving in a circle is at a right angle to ____________. (fill in the blank)
Q 43.
Fill in the blanks :
Universal gravitational constant G = _____________.
Q 45.
As you climb up a mountain, your ears “pop” because of the changes in atmospheric pressure. In which direction, outward or inward, does your eardrum move when you climb up?
Q 46.
Loaded test-tube placed in pure milk sinks to a certain mark (M). Now some water is mixed with the milk. Will the test tube sink more or less? Explain.
Q 47.
A cuboid room has dimensions 50m x 15m x 3.5m. What is the mass of the air enclosed in the room if the density of air = 1.30 kg/m
3.
Q 48.
A solid block of density 6000 kg/m
3 weighs 0.6 kg in air. It is completely immersed in water of density 1000 kg/m
3. Calculate the apparent weight of the block in water and the buoyant force. (Take g = 10ms
-2)
Q 49.
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 50.
The gravitational force between two objects is 100 N. How should the distance between these objects be changed so that force between them becomes 50 N ?
