MDCAT Work and Energy MCQs 2026 | KE, PE, Power

What MDCAT 2026 asks in Unit 39 Work and Energy

PMDC Unit 3 is short on the page and long in the options. The stem will give you F, s and an angle, or m, v and a height, and the distractors will be the same numbers multiplied without the ½, without the cosine, or with power written as energy.

Work is the scalar product $W=Fs$ cos $\theta$. Kinetic energy is ½mv² — doubling v quadruples KE. Gravitational PE is mgh with a reference you are allowed to slide; only differences do work. The work–energy theorem says net work equals $\Delta K$ E, including negative work from friction. Power is W/t or Fv. Efficiency is useful over input, never more than one.

Twenty conceptual MCQs, each unlocking a lab: PE sliding into KE, friction eating work, power as Fv.

• $W=F\cdot s$ = Fs cos $\theta$. A force perpendicular to the displacement does no work. A static hold ($s=0)$ does no work.
• $KE=\frac{1}{2}m{v}^2.$ Dropping the ½ is the numerical trap. Doubling speed multiplies KE by four.
• $PE=mgh.$ Move the floor: the difference is what matters.
• Work–energy theorem: $W_{net}=\Delta K$ E. Friction’s work is negative.
• $P=Fv$ = W/t. Do not confuse joules with watts.
• $\eta =W_{out}/E_{in}\le 1.$

Often-asked Work and Energy MCQ patterns

These are the Work and Energy ideas that keep coming every year with new numbers.

• $10\mathrm{N}$ through $4\mathrm{m}$ at $60^{\circ }:W=20$ J, not $40\mathrm{J}$.
• KE of $2\mathrm{kg}$ at $4m/s$ is $16\mathrm{J}$, not $32\mathrm{J}$ (missing ½) and not $8\mathrm{J}$ (using mv).
• A porter holding a suitcase does no work on it. Tired is not the definition.
• A drop from rest: mgh becomes ½mv², so $v=\sqrt{2gh}.$ With $g=10,5\mathrm{m}$ gives $10m/s$.

Worked Work and Energy numericals ($g=10)$

Work these on paper first. Then open the Unit 39 quiz — the same numbers are in the questions, with wrong options built from the usual mix-ups.

Work and Energy 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 Fs when the angle is $60^{\circ }$.
• Writing $KE=m{v}^2$ without the ½.
• Counting a static hold as work — if $s=0,W=0.$
• Confusing power (watts) with energy (joules).
• Efficiency greater than 1 ‘because of the machine’.
• Using the wrong PE reference as if the number itself were sacred.

Work and Energy formula sheet for MDCAT 2026

Write these until they are cheaper than thinking. Then open the Work and Energy quiz and make the picture agree.

• $W=Fs\cos \theta$
• $KE=\frac{1}{2}m{v}^2$
• $PE=mgh$
• $\Delta KE=W_{net}$
• $P=Fv=W/t$
• $\eta =W_{out}/E_{in}$

How to practise Unit 39 Work and Energy MCQs

Ask three questions of every stem: is there a displacement along the force? is speed changing? is time or rate involved? That splits work, energy and power.

Write the ½ in KE before you punch numbers. Most misses in this unit are a missing half or a missing cosine.

Open the Work and Energy quiz after Unit 2. The labs make PE slide into KE in front of you.

Choose topics and a test length up to 180 from the 872-question bank. Tutor Mode explains each selection; Timed Exam reveals explanations on submission. Use the complete review to revise mistakes and download your results.