State Newton’s law of gravitation.
State Newton’s law of gravitation.
Ans: – Newton’s law of gravitation state the force of attraction between the masses of that object and the distance between them.
Or, F=Gm1 × m2/ r^2.
How does the force of gravitation between two objects change when the distance between them is doubled?
Ans: – As we all know gravitational force of attraction is depends inversely to the square of the distance between them so the when the distance will be double then the force will be 1/4th of the previous one.
How does the gravitational force between two objects change if the masses of both objects are doubled?
Ans: – As, F=Gm1m2/r^2.
So, when masses are double then the force will be 4F.
Derive an expression for the acceleration due to gravity on the surface of the earth in terms of earth’s mass, gravitational constant and radius of earth.
Ans: – Let masses of two object is m1 and m2 and the distance between them is r.
So, according to Newton’s principal F~m1×m2 and F~1/r^2.
Then, F~m1×m2/r^2.
Or, F=Gm1×m2/ r^2. Where G is universal gravitational constant.
Write the equations of motion of an object moving or falling only under gravity.
Ans: – The equation of motion of an object moving or falling only under gravity is F=mg, where m=mass, g= acceleration due to gravity.
What are the differences between the mass of an object and its weight? On what factors does the weight of an object depend?
Ans: – The mass of an object is the only the sum of masses of different particles present in it and the weight of any object is determined by the multiplication of the mass and the gravitational constant.
This weight is depending on the gravitational acceleration and the height from the earth.
Why does a capped empty plastic bottle released under water bounces back to the surface of water?
Ans: – We all know that when an object is placed in water then the object deflects by the buoyancy forces of the water. For this reason, the plastic bottle released under water bounces back to the surface of water.
What is force of buoyancy? What are the factors on which the magnitude of the buoyant force acting on a body at a given place depends?
Ans: – When we place an object in liquid or water then the water or the liquid exert pressure on the object which is immersed in water this force is known as the buoyancy forces.
State Archimedes’ principle. Give two applications of Archimedes’ principle.
Ans: – The Archimedes principal states that if a body is immersed in a fluid, then the body experiences an upward force which equal to the weight of the fluid displaced by it. This principal depends on
(i) density of the fluid and (ii) volume of the body immersed in the fluid.
If the average distance between the earth and the sun is 1.5 × 1011 m, calculate the force of gravitation between the two. Given:
mass of the earth = 6 ×1024 kg
mass of the sun = 2 ×1030 kg
value of G = 6.7 ×10–11 Nm2kg–2.
Ans: – The force of gravitation is, f=G×m1×m2/R^2.
Here, m1=6×10^24kg and m2=2×10^30kg, G=6.7×10^-11.R=1.5×10^11m.
Then, f=6.7×10^-11×6×10^24×2×10^30 / (1.5×10^11).
Or, f= 53.6×10^32 N.
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