Advertisements
Advertisements
प्रश्न
A person brings a mass of 1 kg from infinity to a point A. Initially the mass was at rest but it moves at a speed of 2 m s −1 as it reaches A. The work done by the person on the mass is −3 J. The potential at A is
विकल्प
−3 J kg−1
−2 J kg−1
−5 J kg−4
none of these.
Advertisements
उत्तर
−5 J kg−4
The work done by the person is equal to the kinetic energy and the potential energy of the mass of 1 kg at point A.
Let VA be the potential at point A.
\[\text { Now }, W = \frac{1}{2}m v^2 + \left( P . E . \right)_A \]
\[ \Rightarrow W = \frac{1}{2}m v^2 + V_A \times m\]
\[ \Rightarrow - 3 = \frac{1}{2} \times 1 \times (2 )^2 + V_A \times 1\]
\[ \Rightarrow V_A = - 5 J/Kg\]
APPEARS IN
संबंधित प्रश्न
What happens to the force between two objects, if the distance between the objects is doubled and tripled?
Inside a uniform spherical shell
(a) the gravitational potential is zero
(b) the gravitational field is zero
(c) the gravitational potential is same everywhere
(d) the gravitational field is same everywhere
Two spherical balls of mass 10 kg each are placed 10 cm apart. Find the gravitational force of attraction between them.
Three uniform spheres each having a mass M and radius a are kept in such a way that each touches the other two. Find the magnitude of the gravitational force on any of the spheres due to the other two.
Two concentric spherical shells have masses M1, M2 and radii R1, R2 (R1 < R2). What is the force exerted by this system on a particle of mass m1 if it is placed at a distance (R1+ R2)/2 from the centre?
A uniform metal sphere of radius a and mass M is surrounded by a thin uniform spherical shell of equal mass and radius 4a (In the following figure). The centre of the shell falls on the surface of the inner sphere. Find the gravitational field at the points P1 and P2 shown in the figure.
The mass of moon is about 0.012 times that of earth and its diameter is about 0.25 times that of earth. The value of G on the moon will be:
How will the force of gravitation between two objects change if the distance between them is:
Infinite
A ball is thrown up with a speed of 4.9 ms-1.
Calculate the maximum height it would gain before it begins to fall.
Where will you weigh more: at the moon's surface or at the earth's surface?
At what height above the earth's surface would the value of acceleration due to gravity be half of what it is on the surface? Take the radius of earth to be R.
Two equal and opposite forces acting at the same point on a stationary body. Will the body move? Give reason to explain your answer.
Explain why:
The atmosphere does not escape.
State Newton's universal law of gravitation. Express it with the mathematical form of force of gravitation?
Choose the wrong option.
Six point masses of mass m each are at the vertices of a regular hexagon of side l. Calculate the force on any of the masses.
If three equal masses m are placed at the three vertices of an equilateral triangle of side 1/m then what force acts on a particle of mass 2m placed at the centroid?
A hollow spherical shell of uniform density exerts what gravitational force on a point mass placed inside it?
For an object outside a uniform solid sphere, from where is the sphere's mass considered to act?
