Calculate work done, kinetic and potential energy, and the rate energy is transferred or converted — nearly everything here connects back to one idea, the conservation of energy, tracked as it changes form. Every question comes with a written walkthrough of exactly where the energy went.
W = Fd only applies directly when the force is in the same direction as the motion — a force applied at an angle only contributes its component along the direction of motion, which is why the full formula includes cos(θ).
Conservation of mechanical energy (kinetic plus potential) only holds when no external forces like friction remove energy from the system — with friction present, some mechanical energy converts to heat and the total mechanical energy decreases.
Work measures the total energy transferred, while power measures how quickly that transfer happens — two situations can involve the same amount of work but very different power if one takes much longer than the other.
Straight from the bank — one per difficulty tier. Reveal the answer to see the explanation you'd get in a real session.
A 20 kg box is lifted 3 meters straight up at constant velocity. Using g = 10 m/s², how much work is done against gravity?
A 4 kg object is moving at 6 m/s. What is its kinetic energy?
A 2 kg ball is dropped from a height of 10 meters. Using g = 10 m/s², and ignoring air resistance, what is the ball's speed just before it hits the ground?
Work, energy, and power problems reward tracking where energy goes — from potential to kinetic, or from work done to power delivered over time — rather than memorizing formulas in isolation.
For every problem, state which form of energy is present at the start and what it converts into by the end. Untimed practice is where that tracking habit sticks.
Move to timed sessions once the work, kinetic energy, and potential energy formulas are instant recall.
Pair work, energy, and power with kinematics in a mock — both describe the same motion from different angles.
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