Centripetal Force

Question 1

What’s the equation for force?

Answer 1

F = mv²/r

F = Force (N)
m = Mass (kg)
v = Velocity (m/s)
r = Radius

Question 2

What are the different types of force that are calculated in circular motion?

Answer 2

> Friction
Magnetic / electric force
Tension (of a string)

Question 3

What is the relationship between time period and frequency?

Answer 3

> Inverse proportion
[T = 1/f]
[f = 1/T]

Question 4

What is the diameter of a full circle?

Answer 4

2πr

Question 5

What is the equation of angular velocity (ω) ?

Answer 5

> v = 2πr /T = 2πfr
ω = 2πf
( ∴ v = ωf )

where f is the frequency of rotation

Question 6

How is angular velocity (ω) measured?

Answer 6

> radians per second

> rads⁻¹

Question 7

What is the vertical component of an object the product of?

Answer 7

> Mass x weight

> mg

Question 8

What is the physical relationship between velocity and the centre of the circle?

Answer 8

Velocity is always at a tangent (consequently 90ᵒ) to the centre of the circle

Question 9

How do you calculate 1 radian?

Answer 9

1 radian = 360 / 2π

Question 10

How do you calculate the angle of a sector?

Answer 10

θ = s / r

> s = arc length
r = radius

Question 11

What is the equation of centripetal acceleration (a) ?

Answer 11

As v = ωr
a = ω²r

( r is not squared, otherwise we’d be calculating the acceleration of an object of larger radius )