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प्रश्न
Explain what is meant by the equation :
`g= Gxxm/r^2`
where the symbols have their usual meanings.
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उत्तर
g = GM /R2
This is an equation , which expresses acceleration due to gravity. It states that acceleration due to gravity (g) can be calculated as a product of the Gravitational Constant (G), which is 6.673 × 10−11 Nm2 kg−2 and mass of the planet (M) i.e., 5.98 × 1024 kg in case of the earth divided by square of radius of that planet (R), i.e., 6.4 ×106 m for earth. This is an equation, which expresses acceleration due to gravity. By putting the respective values for earth, g can be calculated as 9.8 m/s2.
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संबंधित प्रश्न
What is the force of gravity on a body of mass 150 kg lying on the surface of the earth? (Mass of earth = 6 x 1024 kg; Radius of earth = 6.4 x 106 m; G = 6.7 x 10-11 Nm2/kg2)
What do you understand by the term 'acceleration due to gravity of earth' ?
Name the force which stops you falling through the floor.
Choose one or more correct alternatives.
Which of the forces involved in dragging a heavy object on a smooth, horizontal surface, have the same magnitude?
- The horizontal applied force
- gravitational force
- reaction force in vertical direction
- force of friction
Figure shows the velocity-time graph of a particle of mass 100 g moving in a straight line. Calculate the force acting on the particle.
(Hint : Acceleration = Slope of the v-t graph)
A car is moving with a uniform velocity 30 ms-1. It is stopped in 2 s by applying a force of 1500 N through its brakes. Calculate the following values : The retardation produced in car.
Write scientific reason.
The value of gravitational acceleration (g) decreases as we go deep inside the earth.
Define acceleration due to gravity.
The mass of planet ‘X” is four times that of the earth and its radius is double the radius of the earth. The escape velocity of a body from the earth is 11.2 × 103 m/s. Find the escape velocity of a body from the planet 'X’.
Read the given passage carefully and answer the questions.
We know that the force of gravity due to the earth acts on each and every object. When we were holding the stone in our hand, the stone was experiencing this force, but it was balanced by a force that we were applying on it in the opposite direction. As a result, the stone remained at rest. Once we release the stone from our hands, the only force that acts on it is the gravitational force of the earth and the stone falls down under its influence. Whenever an object moves under the influence of the force of gravity alone, it is said to be falling freely. Thus the released stone is in a free fall. In free fall, the initial velocity of the object is zero and goes on increasing due to the acceleration due to the gravity of the earth. During free fall, the frictional force due to air opposes the motion of the object and a buoyant force also acts on the object. Thus, true free fall is possible only in a vacuum.
1) Complete the following statement by choosing the right option.
The stone held in the hand is stable because on it __.
- two unbalanced forces are exerted.
- only the gravitational force of the earth is exerted.
- gravitational force of the earth is not exerted.
- two balanced forces are exerted.
2) Why does free fall not happen on the earth?
3) Why does the velocity of the object increase during the free fall?
4) Which type of force exerts on the object during free fall?
5) Why does free fall happen only in a vacuum?
