Orbital Velocity

Q.

Periodic time of a satellite revolving above Earth’s surface at a height equal to R, where R the radius of Earth, is [g is acceleration due to gravity at Earth’s surface]

1. $2\pi \sqrt{\frac{2R}{g}}$

2. $4\sqrt{2}\pi \sqrt{\frac{R}{g}}$

3. $2\pi \sqrt{\frac{R}{g}}$

4. $8\pi \sqrt{\frac{R}{g}}$

Q.

What is the principle of working of a rocket?

Q.

A planet revolving in elliptical orbit has:

A. a constant velocity of revolution.

B. has the least velocity when it is nearest to the sun.

C. its areal velocity is directly proportional to its velocity.

D. areal velocity is inversely proportional to its velocity.

E. to follow a trajectory such that the areal velocity is constant.

1. $A$only

2. $E$only

3. $D$only

4. $C$only

Q. Why the space rockets are generally launched from west to east?

Q.

Which of the following is not a projectile?

1. An aircraft taking off

2. A ball is thrown horizontally from a roof

3. A bullet fired from a rifle

4. A football kicked by a player​.

Q. With what velocity should a particle be projected so that it attains a height equal to radius of Earth ?

Q.

If earth rotates faster than its present speed the weight of an object will

1. increases at the equator but remain unchanged of the poles.

2. decreases at the equator but remain unchanged at poles.

3. remain unchanged at the equator but decreases at poles.

4. remain unchanged at the equator but increases at the poles.

Q.

The escape velocity of a particle of mass $m$ varies as

1. $m^2$

2. $m$

3. $m^0$

4. $m^{-1}$

Q. Time period of revolution of a nearest satellite around a planet of radius R is T. Period of revolution around another planet, whose radius is 3R but having same density is

1. T
2. 3 T
3. 9 T
4. $3\sqrt{3}T$

Q.

Rocket can move in air free space, but jet planes cannot. Why?

Q. Find the value of acceleration due to gravity near the surface of the earth.

Q.

A satellite orbiting about Earth does not fall down because of ___________.

1. the escape velocity provided to it.

2. the gravitational pull of the sun.

3. the orbital velocity provided to it.

4. the weightlessness of the satellite.

Q. A body is orbiting around the earth at mean radius 16 times as great as the parking orbit of a satellite. The period of the body is:
a)12 days
b)64 days
c)34 days
d)44 days

Q. On decreasing the height of a satellite its time period will increase or decrease?

Q. The motion of moon around earth can be described as:

1. free fall under gravity
2. free fall without any gravitational force
3. linear motion
4. periodic motion

Q.

The period of revolution of a geostationary satellite is _________ that of the period of rotation of the Earth.

1. equal to

2. greater than

3. less than

4. A and C

Q.

communication satellite moves in the orbit of radius 44400 km around the earth. the acceleration of such a satellite assuming that the only force acting on it is that due to the earth is

A)0.4 mps

B)0.6mps

C)0.2mps

D)0.1mps

Q.

Rocket can move in air free space but a jet plane cannot.why?

Q.

Two identical geostationary satellites are moving with equal speed in the same orbit but their sense of rotation brings them on a collision course. The debris will

(1) Fall down

(2) Move up

(3) Move east to west in same orbit

(4) Move from West to East in same orbit

Q.

A satellite circles the earth in an orbit whose radius is twice the earth’s radius. The mass of earth is $6\times {10}^{24}kg$ and its radius is $6.4\times {10}^{6}m$. The time period of the satellite is approximately

1. $14346s$

2. $2yr$

3. $84h$

4. $1h$

Q.

An astronaut orbiting the earth in a circular orbit of 120 km above the earth's surface, gently drops a spoon out of the spaceship. The spoon is likely to:

1. fall vertically down to the earth surface.

2. move in an irregular way and then fall down to earth.

3. move towards the moon.

4. move along with the spaceship.

Q. Jupiter ranks ______, among the brightest objects in the night sky.

1. $1^{\text{st}}$
2. $2^{\text{nd}}$
3. $3^{\text{rd}}$
4. $4^{\text{th}}$

Q. Time period of revolution is T for any satellite revolving around a planet of radius R. The period of revolution for the satellite around another planet having the same density($\rho$) radius as 3R, is__. (Assume the satellite to be very near to the planet's surface)

1. T
2. 3 T
3. 9 T
4. $3\sqrt{3}T$

Q.

With respect to a satellite going around the earth in a circular orbit, which of the following statements are wrong?

1. It is a freely falling body.

2. It suffers no acceleration.

3. Its angular momentum remains constant.

4. It is moving at a constant speed.

Q. How can we take accelaration of a body in the upwards direction as positive? Since it is going against the gravity of the Earth must'nt it be taken as negative?

Q.

Which has a longer time period a satellite revolving close or away from the surface of the earth

Q.

A satellite $X$ is launched into a circular orbit of radius $R$ around the earth while a second satellite $Y$ is launched into an orbit of radius $4R$. The ratio of the time periods of $Y$ to $X$ is ______.

1. $1$

2. $4$

3. $8$

4. $16$

Q.

Two stones of masses 2 kg and 5 kg are released from the top of a tower. Which stone will reach the ground first?

Q. a satellite is revolving round the earth with orbital speed v₀ if it stops suddenly, the speed with which it will strike the surface of earth would be-( v_e=escape velocity of particle n earth surface)

Q.

Reynolds number (Re) is___

1. an experimental number used to predict the flow velocity.

2. a number with certain dimensions

3. a non-dimensional velocity

4. a number which differentiates between types of flows like laminar, turbulent and transsitional.