H2 Physics - Circular Motion

Define period (of a body in circular motion)

It is the time taken for the body to make one complete revolution.

Define frequency (of a body in circular motion)

It is the number of revolutions made per unit time

Define angular displacement

It is the angle a body rotates through with respect to its initial position

Define the radian

It is the angle subtended by an arc length equal to the radius of the arc

State the formula for the angle measured in radians

θ = s/r

Define angular velocity

It is the rate of change of angular displacement with respect to time

State the equation which relates linear and angular velocity

v = rω

State the equation which related angular velocity with period, and hence, frequency

• ω = 2π/T

• ω = 2πf

State the equation which relates period with linear speed

T = 2πr/v

State the 3 formulae for centripetal acceleration

a_c = vω = rω² = v²/r

State the formula for the angle made by the string and vertical of a pendulum given the linear velocity and radius of rotation

θ = tan⁻¹(v²/rg)

State the minimum linear speed an object must possess to be in contact with a vertically circular path at the top

√gr

State the minimum linear speed an object must possess at the bottom to be in contact with a vertically circular path throughout

√5gr