This is how every problem is set out in the paid packs: what is given, the formula, each step with units, and the final answer. Try the question first, then compare your steps.
A torch bulb of resistance 6 Ω is connected to a 3 V battery. Find the current in the bulb and the charge that flows through it in 1 minute.
Watch out: change minutes to seconds before using Q = It.
In a hydraulic lift, a force of 50 N is applied to a small piston of area 2 cm². The large piston has an area of 200 cm². What load can the large piston lift?
Watch out: both areas must be in the same unit; here cm² cancels, so no conversion is needed.
A 1000 kg car goes round a flat bend of radius 50 m. The maximum friction between the tyres and the road is 8000 N. What is the fastest speed the car can take the bend without skidding?
Watch out: above 20 m/s the car slides off along the tangent, not straight outwards.
An astronomical telescope has an objective of focal length 100 cm and an eyepiece of focal length 5 cm. Find its magnifying power and the length of the tube in normal adjustment.
Watch out: in normal adjustment the final image is at infinity, so the lens separation is exactly fo + fe.
A particle moves in simple harmonic motion with amplitude 0.05 m and period 2 s. Find its maximum speed and maximum acceleration.
Watch out: maximum speed is at the centre of the motion; maximum acceleration is at the ends.
A flywheel with moment of inertia 4 kg m² starts from rest. A constant torque of 8 N m acts on it for 5 s. Find its angular acceleration, its final angular velocity and its rotational kinetic energy.
Watch out: check: the torque turns the wheel through θ = ½αt² = 25 rad, and work τθ = 8 × 25 = 200 J, the same answer.
Each pack will cover all the units of one level in this format, with exam-style questions, marking schemes and common mistakes, as a PDF for your phone or to print. The packs are coming soon.
Tell me when it is ready