Advertisements
Advertisements
Question
Right or wrong sentence:
The value of gravitational acceleration at the centre of earth is zero.
Options
Right
Wrong
Advertisements
Solution
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
RELATED QUESTIONS
What do you mean by acceleration due to gravity?
What is the acceleration of free fall?
A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity just before touching the ground.
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.
What is the acceleration produced in a freely falling body of mass 10 kg ? (Neglect air resistance)
State whether the following statement is true or false :
A falling stone also attracts the earth.
Why does a sharp knife cut objects more effectively than a blunt knife ?
Explain why, the tip of a sewing needle is sharp.
Name the force which pulled the apple off Isaac Newton’s tree.
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 ?
A stone is thrown vertically upwards with initial velocity u reaches a height ‘h’ before coming down. Show that the time taken to go up is the same as the time taken to come down.
What would be the value of ‘g’ on the surface of the earth if its mass was twice and its radius half of what it is now?
The total energy of an object falling freely towards the ground ______.
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 force acts for 0.1 s on a body of mass 2.0 kg initially at rest. The force is then withdrawn and the body moves with a velocity of 2 m s-1. Find the magnitude of the force.
How is the acccelaration due to gravity on the surface of the earth realted to its mass and radius ?
What is escape velocity?
The free fall of an object is possible only in ______.
Write scientific reasons.
When we drop a feather and a stone at the same time from a height the stone reach the earth faster than a feather.
The mass and weight of an object on earth are 5 kg and 49 N respectively. What will be their values on the moon? Assume that the acceleration due to gravity on the moon is 1/6th of that on the earth.
