Circular Motion
What is uniform circular motion?
Uniform circular motion is when an object moves in a circle at a steady, fixed speed
What is escape velocity?
the minimum speed an object needs to break free from a planet's gravitational pull and fly into space without using any more power.
What is the value of G, the universal gravitational constant?
6.67 × 10⁻¹¹ N m²/kg²
What is centripetal force?
Centripetal force is the net inward force directed toward the center of a circular path that keeps an object moving in a circle
Does escape velocity depend on the mass of the escaping object? Explain
No, escape velocity does not depend on the mass of the escaping object
What is the mass of the Earth?
6 × 10²⁴ kg
In which direction does centripetal force act?
towards the center
Why does a person feel weightless in an orbiting spacecraft?
An astronaut feels weightless in an orbiting spacecraft not because gravity is absent, but because both the person and the spacecraft are in a constant state of free fall toward Earth
What is the approximate gravitational force between the Earth and Moon?
2 × 10²⁰ N
Why does the Moon not fly away from Earth?
Gravity Is Always Pulling the Moon Toward Earth- centripetal force
Why is g less on the Moon than on Earth?
the Moon has a much smaller mass
What is the mass of the Sun?
1.96 × 10³⁰ kg
What would happen to an object moving in a circle if the centripetal force suddenly disappeared?
The object will break away from the circular path and fly off in a straight line
Think: If Earth suddenly had twice its present radius but the same mass, would g increase or decrease? Explain.
decrease to one-fourth of its present value because surface gravity depends inversely on the square of the radius.
What is the relationship between g and G?
g = GM/R²