WorksheetsThursday week 6 grav forces/ fields and orbitals
Total questions: 22
Worksheet time: 14mins
We generally think of satellites of small mass in orbit around bodies of much larger mass. In the case of two bodies of equal mass is it proper to treat one as being at the centre and the other as its satellite?
The two bodies can be treated as each being in orbit around a point in space equidistant between them.
The equal bodies collide rather than orbit each other, so the situation does not arise.
It is possible for a heavenly body to have a moon equal to its own mass, but the separation would need to be 2r for the system to be stable.
If a 'moon's' mass is too large, gravitational attraction will exceed the centripetal force needed to keep it in orbit, therefore the situation is unstable in the long term.
Which of the following statements is true about the gravitational field around a body?
A gravitational field only exists around the body if there is a test mass nearby to be attracted to it.
A gravitational field exists around the body even if there is no test mass nearby but the field has no direction.
A gravitational field exists around the body even if there is no test mass nearby and the field points inwards towards the body.
The direction of the gravitational field around the body depends on the position of a test mass placed nearby.
What are the units of the gravitational constant, G?
r3=4π2GMT2
N kg m−2
N m kg−2
N kg−2 m2
A body of mass 20 kg mass is placed 4 m above the Earth's surface. The value of g may be taken as 10 ms-2.
What are the gravitational field strength and gravitational force acting on the body?
A
B
C
D
The radius of the Earth may be taken to be 5760 km. A satellite is in a circular orbit 144 km above the Earth's surface. What is the approximate value of the gravitational force on the satellite compared with that when it is at the Earth's surface?
greater by 10%
greater by 5%
less by 5%
less by 10%
Each diagram below shows the variation of the gravitational potential energy U and the gravitational force F of a point mass with its distance r from another point mass.
Which one of the diagrams is correct?
In an elliptical orbit, you will be travelling the fastest at the...
Midpoint
Vertex
Apoapsis
Periapsis
In an elliptical orbit, the point farthest away from the object you are orbiting is called the...
Apoapsis
Pariapsis
Directrix
Hyperbola
Which planet will take the least amount of time to revolve around the Sun?
Mercury
Venus
Earth
Mars
What this means is that if a satellite moves away from what it is orbiting,
Kepler's 3rd law tell us that __ would be dependent on __.
orbital period ; distance
distance ; orbital period
If a planet's orbital radius is doubled, what happens to the length of a year on that planet?
