Chapter 16: Circular Motion.

Question 1

What should we do to make answering and understanding these type of questions easier?

Answer 1

Draw what is happening. Including what we know and what we don’t know (with labels).

Question 2

What is Angular Speed?

Answer 2

The rate at which a line rotates a about the centre of an object.

Question 3

What is 1rpm (1 rotation per minute) equal to in radians?

Answer 3

1rpm = 2π/60 rad/s (radians per second).

Question 4

What is the formula for Angular Speed?

Answer 4

ω = θ/t.

• ω - Angular Speed - radians/ second.
• θ - Angle moved through - Radians.
• t - time taken - seconds.

Question 5

What is the formula for Arc Length?

Answer 5

AB = rθ.

• r = radius of circle - metres.
• θ = Rotation about the centre - radians.

Question 6

What is the formula for Linear Speed?

Involving Angular Speed…

Answer 6

v = rω.

• v = Angular Speed - metres per second.
• r = radius of circle - metres.
• ω - Angular Speed - radians/ second.

Question 7

What direction to a circle does Linear Speed happen?

Answer 7

A tangent to a circle.

Question 8

What is the name of the force which acts towards the centre of a circle?

Answer 8

Centripetal Force.

Centrifugal Force = Moving away from circle.

Question 9

What equation(s) lets you express the magnitude of acceleration?

Answer 9

• a = rω².
• (v = rω).
• (ω = v/ r).
• a = v²/ r.

Question 10

How do you find the Centripetal Force?

Equation(s)?

Answer 10

• F = ma.
• F = mrω².
• F = mv²/r.