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SI unit of gravitational constant is __________.
We know that:
Thus we get, [G] = [F.R^{2} / m^{2} ] = [F] x L^{2} x M^{2 }= [F] M^{2} L^{2 }= N kg^{2} m^{2}
From Newton’s law of gravitation,
Since, Force (F) = Mass × Acceleration = M × [LT^{2}]
∴ The dimensional formula of force = M^{1} L^{1} T^{2}
⇒ Gravitational Constant (G) = F × r^{2} × [m_{1}m_{2}]^{1}
Or, G = [M^{1} L^{1} T^{2}] × [L]^{2} × [M]^{2} = [M^{1} L^{3} T^{2}].
Therefore, the gravitational constant is dimensionally represented as [L]^{3 }[M]^{1 }[T]^{}^{2}.
Tides refer to the rise and fall of our oceans' surfaces. It is caused by the attractive forces of the Moon and Sun's gravitational fields as well as the centrifugal force due to the Earth's spin.
Two bodies with same mass “m” separated by a distance “r” exert a gravitational force of F on each other. Suppose the distance between them is doubled and the force becomes F’. The ratio of two forces is
We know that the force of gravitation is inversely proportional to square of the distance between the two bodies,
i.e. F∝ r^{2}
Hence, when the distance between them will be doubled, the force will be reduced by 4 times
So, the ratio will be 4:1
The mass of the body on moon is 40kg, what is the weight on the earth.
Weight = Mass * Accelertion due to gravity = 40 * 9.8 = 392 N
The value of G is universally constant = 6.67 × 10^{8} dyne.cm^{2}/g^{2}
We know:
1 dyne = 10^{5} N
1 cm = 10^{2} m
1 g = 10^{3} kg
⇒ 6.67 × 10^{8} × ( 10^{5}) .(10^{2})^{2}/(10^{3})^{2} Nm^{2}/kg^{2} = 6.67 × 10^{8} { 10^{5}× 10^{4} /10^{6}} Nm^{2}/kg^{2}
= 6.67 × 10^{8} × 10^{3} N.m^{2}/kg^{2}= 6.67× 10^{11} Nm^{2}/kg^{2}
G is a universal gravitational constant, its value is:
We know that: [g] = [G.m.m / r.r]
Since the unit of G must be same as the unit of g.r.r / m.m i.e. Nm^{2} /kg^{2}
Also, we know that G is very very less than 1 as the gravitational force is a very weak force.
In orbit, objects inside a spacecraft feel weightless:
The gravitational force of the earth acts on every object having mass. When a ball is thrown upwards the gravitational force of the earth acts against the velocity of the object and pulls the ball downwards, i.e, towards itself.
Thus, gravity pulls a ball back to earth.
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