Rotational Kinematics

SI unit of angular displacement, θ

• radian
• meter

• revolution
• degree

Answer explanation

The SI unit for angular displacement is "radian". "Revolution" and "degree" are other units, but not SI units.

SI unit of angular velocity, ω

• degrees per second (°/s)
• radians per minute (rad/min)
• radians per second (rad/s)
• revolutions per second (rev/s)

Answer explanation

SI unit for angular velocity ω is radians per second.

Other unit for ω is rpm and rps. But they are not SI units, you need to convert to rad/s.

SI unit of angular acceleration, α

• kg·m/s²
• rad/s
• m/s²
• rad/s²

Answer explanation

Angular acceleration measures the rate of change of angular velocity, so it’s radians per second squared.

Which formula defines average angular velocity?

• ω = Δθ / Δt

• ω = Δθ Δt

• ω = θ / t

• ω = Δt / Δθ

Answer explanation

Average angular velocity is the change in angular displacement divided by the time taken.

Which formula defines average angular acceleration?

• α = (ωf - ωi) / Δt

• α = ωf / Δt

• α = (ωi - ωf) / Δt

• α = (ωf - ωi) * Δt

How many radians in 4 revolutions?

• 8π
• 4π
• 10π
• 6π

Answer explanation

1 revolution = 2π rad

so 4×2π = 8π rad

Convert 6 rpm to rad/s.

• π​ / 10

• π​ / 5

• π​

• 2 π​

Answer explanation

6 × (2π/60) ​= π/5​ rad/s.

If a wheel took 2 s to make 1 complete rotation, what is its angular velocity?

• 4π radians per second
• 2π radians per second
• 6π radians per second
• π radians per second

Answer explanation

ω = (2π/T) ​

ω = (2π/2) ​​= π rad/s

Which equation of rotational motion is equivalent to (v = u + at) in linear kinematics?

• v = u + ωt
• ω = αt + θ
• ωf = ωi + αt

• θ = u + at

Answer explanation

from these relationships:
s=rθ
v=rω
a=rα

Which of the following correctly matches linear and rotational quantities?

• Displacement ↔ Angular acceleration

• Angular velocity ↔ Angular displacement

• Centripetal acceleration ↔ Angular velocity

• Linear velocity ↔ Angular velocity