MDCAT Rotational Dynamics MCQs 2026 | Centripetal Force

What MDCAT 2026 asks in Unit 40 Rotational and Circular Motion

PMDC Unit 4 translates every linear idea you already know into an angle. Displacement becomes $\theta$ in radians (arc over radius, not 360 in an equation). Velocity becomes $\omega$. Newton II becomes $\tau$ = I $\alpha$. Momentum becomes $L=I\omega .$

Two extra ideas do not have a linear twin. Centripetal acceleration v²/r points to the centre and does no work — it only turns velocity. Rolling without slipping ties the two worlds: $v=r\omega$, and kinetic energy is ½mv² plus ½I $\omega$ ².

Twenty MCQs, each with a spinning lab. A skater pulling arms in is the angular-momentum item; a stone on a string is the centripetal item.

• A radian is s/r. One revolution is 2 $\pi$ rad.
• $v=r\omega ,a_t$ = r $\alpha ,a_c$ = v²/ $r=r\omega {}^2$, toward the centre.
• Centripetal force is the name of the net force toward the centre, not a new extra force.
• $\tau$ = I $\alpha$. I depends on the axis. A hoop about its centre is mR²; a disc is ½mR².
• $L=I\omega .$ No external $torque\Rightarrow L$ conserved. Arms in, I down, $\omega$ up.
• Rolling without slipping: $v=r\omega ,KE=\frac{1}{2}m{v}^2$ + ½I $\omega$ ².

Often-asked Rotational and Circular Motion MCQ patterns

These are the Rotational and Circular Motion ideas that keep coming every year with new numbers.

• Degrees inside $v=r\omega$ — convert, or the number is junk.
• $F_c$ drawn as a third force on a horizontal circle. Tension (or friction, or gravity’s component) already is $F_c$.
• Skater: L conserved, KE not — she does work pulling in.
• Period of circular motion $T=2\pi r/v$ = 2 $\pi /\omega$. Cyclotron $T=2\pi m/qB$ lives in Unit 10, not here.

Worked Rotational and Circular Motion numericals ($g=10)$

Work these on paper first. Then open the Unit 40 quiz — the same numbers are in the questions, with wrong options built from the usual mix-ups.

Rotational and Circular Motion traps that steal the mark

A good option is a true sentence about the wrong quantity. If you miss, the quiz names the mix-up on the option you actually picked.

• Using degrees inside $v=r\omega .$
• Putting centripetal force on a free-body as a new extra force instead of the net towards the centre.
• Forgetting that I depends on axis.
• Writing L conserved when a torque is still acting.
• Dropping ½I $\omega$ ² from rolling KE.
• Saying centripetal force does work because the stone is ‘moving’.

Rotational and Circular Motion formula sheet for MDCAT 2026

Write these until they are cheaper than thinking. Then open the Rotational and Circular Motion quiz and make the picture agree.

• $\theta =s/r$
• $v=r\omega$
• $a_c=v^2/r=r\omega {}^2$
• $\tau =I\alpha$
• $L=I\omega$
• $K{E}_{r}oll=\frac{1}{2}m{v}^2+\frac{1}{2}I\omega {}^2$

How to practise Unit 40 Rotational and Circular Motion MCQs

On every circle stem, write ‘towards the centre’ before you name the force. Then ask which real force is pointing that way.

Keep a two-column page: linear on the left, angular on the right. The exam loves swapping a symbol into the wrong column.

Sit Unit 4 after Vectors (torque is a cross product) and Motion ($a_c$ is just a special acceleration).

Choose topics and a test length up to 180 from the 694-question bank. Tutor Mode explains each selection; Timed Exam reveals explanations on submission. Use the complete review to revise mistakes and download your results.