Chapter 16 - Circular Motion

Question 1

What are radians?

Answer 1

Radians are a measure of angle.
A radian is the angle subtended by the a circular arc with arc length equal to the radius.
2π = 360⁰

Question 2

What is the period in circular motion?

Answer 2

The time in seconds to travel a complete circle. T

Question 3

What is frequency in circular motion?

Answer 3

The number of complete circles travelled per second, measure in Hz. f

Question 4

What is angular velocity?

Answer 4

The rate of change in angle.
ω = θ/t = 2π/T = 2πf

Question 5

Why is an object in circular motion always accelerating?

Answer 5

The direction on motion is constantly changing, therefore the velocity is always changing. Even if the angular velocity is constant. If the velocity is constantly changing, then there must be acceleration.

Question 6

What is centripetal force?

Answer 6

Centripetal force is the net force which act force which acts perpendicular to the direction of the velocity and towards the centre of the circle.

Question 7

What is the equation for velocity in circular motion?

Answer 7

v = 2πr/t = ωr

Question 8

What is the equation for the acceleration in circular motion?

Answer 8

a = v²/r = ω²r

Question 9

What the equation for centripetal force?

Answer 9

F = mv²/r = mω²r

Question 10

How can you investigate circular motion?

Answer 10

Circular motion can be investigated experimentally by tying a bung, with mass m, to a piece of string and threading it through a glass tube. the other end of the string has a mass suspended of it.
F = Mg and F = mv²/r
Mg = mv²/r
Keep r and m constant.
Plot v² against M, should produce a straight line which goes through the origin.