Gravitational Force

Q.

The mass of the moon is $7.34\times {10}^{22}kg$ and the radius is $1.74\times {10}^{6}m$. The value of gravitation force will be

1. 1.45 N/kg

2. 1.55 N/kg

3. 1.75 N/kg

4. 1.62 N/kg

Q.

A body of mass 2 kg is thrown up vertically with K.E. of 490 joule. If the acceleration due to gravity is 9.8 $m/s^2$, then the height at which the K.E. of the body becomes half its original value is given by

1. 50 m

2. 12.5 m

3. 25 m

4. 10 m

Q. mass of a body is (10\pm0.1) kg .Volume is (1\pm0.1) m^{3 }.then the density is given b

Q. A large number of identical point masses m are placed along x-axis, at x = 0, 1, 2, 4 magnitude of gravitational force on mass at origin (x=0), will be

Q.

If the radius of the earth were to shrink by 1% its mass remaining the same, the acceleration due to gravity on the earth's surface would

1. Remain unchanged

2. Decrease by 2%

3. Increase by 2%

4. Increase by 1%

Q. Two blocks A(3kg) and B(6kg) are connected by a spring of stiffness 200 N/m and plaInitially the spring has its equilibrium length. The indicated velocities are imparted to A(1m/s) and B(2m/s. The maximun extension of the spring will be

Q. A black hole is an object whose gravitational field is so strong that even light cannot escape from it.To what approximate radius would earthhave to be compressed to be a black whole

Q. two celestial are separated by some dis†an ce .if the mass of any one of the point like bodies is double while the mass of other is halved then how far should they be taken so that the gravitational force between them become one fourth

Q. 4. A simple pendulum of mass m and length l is held in horizontal position. If it is released from this position, then find the angular momentum of the bob about the point of suspension when it is vertically below the point of suspension. 1. ml2gl 2. mlgl 3. ml3gl 4. None

Q. With reference to the figure, showing a light inextensible string passing over a fixed frictionless pulley find the tension T3. Options 1. 24.5N 2.29.4N 3.18.6N 4. 68.6N

Q.

Weight and normal reaction forces

1. always act opposite to each other.

2. are both contact forces

3. constitute action reaction forces

4. act through the centre of gravity of the body

Q. what will be time period of earth if the radius of the earth is halved?

Q. 40. tunnel is made across the earth at distance R/2 from the center of earth.A particle is dropped (from rest) in the tunnel at one end. If v1 is the speed of particle when passing through the center of tunnel and v2 is the orbital speed of an earth satellite(very close to earthg surface). If v1/v2 = root x +1 / x. Find x.

Q. A package is dropped from an air balloon two times. In the first trial the dis†an ce between the balloon and the surface is H and in second trial 4H. Compare the time it takes for the package to reach the surface in the second trial to that in the first trial?

Q. 10.if the componentsof a force are p along east and p along north directions then the force is

Q.

Two of Jupiter’s moons have orbit radii which differ by a factor of 2. Their periods

1. Differ by a factor of $2\sqrt{2}$

2. Differ by a factor of $\sqrt{2}$

3. Differ by a factor of 4

4. Are the same

Q. A heavy particle is suspended by a string of length l. The particle is given horizontal velocity v_0 . The string become slack at some angle and particle procceds on parabola . Find the value of v_0 if particle passes through point of suspension

Q. State the newton law of gravitation. Hence define G what are the units and dimensions of G? Why is called universal gravitational constant?

Q. a solid cylinder of mass 3kg is rolling on a horizontal surface with velocity 4m/s .it collides with a horizontal spring of force cons†an t 200.the max compression produced in the spring will b

Q. Two satellites of equal mass A and B are revolvingaround earth in circular orbits of radii r and 4rrespectively. Ratio of angular momentum of A and B in their orbit about earth is 1. 1/2 2. 1/ \sqrt2 3. 2 4. \sqrt{2

Q. which of the following statement is correct about a satellite moving around a planet in circular orbit? (1) its time period is proportional to cube of radius (2) its linear momentum is conserved (3) its areal velocity is constant (4) its mechanical energy decreases

Q. the height at which the weight of the body becomes 1/16th , its weight on the surface of earth (radius R) is what

Q. 50.The tension T in the string shown in figure is

Q. 32. Uniform circular motion of a particle is periodic but not shm How??

Q. effect of buoyancy on the the length of the pendulu

Q. 14.A block placed on a rough inclined plane of lenght 4m just begns to slide down when the upper end of the plane is 1m high from the ground .calculate the coefficient of static friction.

Q. Q 7/15 A solid sphere (mass 2M) and a thin hollow spherical shell (mass M) both of the same size, roll down on a rough inclined plane, then a. Solid sphere will reach the bottom first b.Hollow spherical shell will reach the bottomfirst c.Both will reach at the same time dNone of these

Q. A person standing on the floor of an elevator drops a coin. The coin reaches the floor of the elevator in time t₁ if the elevator is stationary and in time t₂ if it is moving uniformly. Then
(a) t₁ = t₂
(b) t₁ < t₂
(c) t₁ > t₂
(d) t₁ < t₂ or t₁ > t₂ depending on whether the lift is going up or down.

Q. Explain, "The centre of gravity of the floating body and the centre of buoyancy are in the same vertical line".

Q.

Which statement is not true about the gravitational forces?

1. Gravitational forces do not form action and reaction pair

2. Gravitational forces are independent of the medium

3. Gravitational forces are conservative forces

4. Gravitational forces are independent of presence or absence of another body