Question:
Is weight a scalar quantity?
Answer:
No. It is a vector quantity.
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.
Why do sewing needles and all pins have a sharp pointed tip?
Q 5.
What is the value of ‘g’ at the centre of Earth ?
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.
Which force is responsible for tides in the ocean at night ?
Q 8.
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 9.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 10.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 11.
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 12.
What do we call the gravitational force between the Earth and an object ?
Q 13.
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 14.
What do you mean by acceleration due to gravity ?
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.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 17.
What is the importance of universal law of gravitation ?
Q 18.
Who measured the value of G first time, experimentally?
Q 19.
What is value of ‘g’ on Earth ?
Q 20.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 21.
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 22.
Mass of an object is 10 kg. What is its weight on the Earth? (g = 9.8 m/s
2.)
Q 23.
Distinguish between mass and weight.
Q 24.
What happens to 'g' experienced by a body when it moves up the earth's surface?
Q 25.
Fill in the blanks :
Universal gravitational constant G = _____________.
Q 26.
A body is projected upwards. What is its velocity at maximum height
Q 28.
Why will a sheet of paper fall slower than one that is crumpled into a ball?
Q 29.
Why does a block of plastic released under water come up to the surface of the water?
Q 30.
A stone drops from the edge of the roof.It passes a window 2 m high in 0.1 s.How far is the roof above the top of the window
Q 31.
An object is thrown vertically upwards and rises to a height of 10 m. Calculate (i) the velocity with which the object was thrown upwards and (ii) the time taken by the object to reach the highest point.
Q 32.
Fill in the blanks :
When objects of different masses and sizes are dropped from same height would reach the ground at ______ (same time/different times), considering negligible air resistance.
Q 33.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go downwards from the earth's surface.
Q 34.
Does the force of attraction between two objects depend on the properties of intervening medium?
Q 35.
The weight of a man is 690N which contains 5.3 x 10
-3 m
3 of blood. Find (a) blood's weight. Take density of blood is 1060 kg/m
3 (b) express it as a percentage of body weight.
Q 36.
What do you mean by Thrust or Buoyant force?
Q 37.
Write the formula to find the magnitude of the gravitational force between the Earth and an object on the surface of the Earth.
Q 38.
Why is the weight of an object on the Moon (l/6)th its weight on the Earth ?
Q 39.
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 40.
Does value of ‘g’ vary from place to place on Earth ?
Q 41.
A body is just dropped from a height What is its initial velocity ?
Q 42.
What is the SI unit of weight ?
Q 43.
In free fall, will heavier objects accelerate more than light ones ?
Q 44.
Can a body have mass but no weight ?
Q 45.
Can you calculate mass of Earth from Newton’s law of gravitation ?
Q 46.
Write down the equations of motion of objects under the influence of gravitational force of Earth.Explain the meaning of the symbols used.
Q 47.
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 48.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go upwards from the earth's surface.
Q 49.
Fill in the blanks :
The SI unit of weight is _____.
Q 50.
Fill in the blanks :
The value of G was found out by _______ by using a ________.
