Advertisements
Advertisements
प्रश्न
Right or wrong sentence:
The value of gravitational acceleration at the centre of earth is zero.
विकल्प
Right
Wrong
Advertisements
उत्तर
The given sentence is right.
Explanation:
Gravity is a vector. By symmetry (Newton’s shell theorem) the gravitational pull of all mass elements around the centre cancels at the centre, so the net gravitational acceleration there is zero. For a uniform spherical Earth, one finds `M(r) ∝ r^3 so g(r)`
= `G·M(r)/r^2 ∝ r`
Hence, g(0) = 0
APPEARS IN
संबंधित प्रश्न
A stone is thrown vertically upward with an initial velocity of 40 m/s. Taking g = 10 m/s2, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?
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.
The values of g at six distances A, B, C, D, E and F from the surface of the earth are found to be 3.08 m/s2, 9.23 m/s2, 0.57 m/s2, 7.34 m/s2, 0.30 m/s2 and 1.49 m/s2, respectively.
(a) Arrange these values of g according to the increasing distances from the surface of the earth (keeping the value of g nearest to the surface of the earth first)
(b) If the value of distance F be 10000 km from the surface of the earth, state whether this distance is deep . inside the earth or high up in the sky. Give reason for your answer.
A pressure of 10 Pa acts on an area of 3.0 m2. What is the force acting on the area ? What force will be exerted by the application of same pressure if the area is made one-third ?
What will be the weight of a person on earth, who weighs 9N on the moon?
i) If g = GM/r2 then where will the value of g be high at Goa Beach or on top of Mount Everest?
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
A force of 10 N acts on a body of mass 5 kg. Find the acceleration produced.
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.
Define the term acceleration due to gravity? Write its S.I. unit.
How is the acccelaration due to gravity on the surface of the earth realted to its mass and radius ?
How are g and G realated ?
What do you understand by the free fall?
The free fall of an object is possible only in ______.
Write the acceleration due to gravity value on the surface of Earth.
Distinguish between:
Universal gravitational constant – Gravitational acceleration of earth.
Write a short note.
Free Fall
