Challenges
Train your physics intuition
Bite-size problems with instant feedback. Earn XP and climb the levels — every correct answer counts once.
Brake to a stop
A car travels at 25 m/s and decelerates uniformly at 5 m/s². How far does it travel before stopping?
Optimal launch
A ball is launched at 20 m/s at 45° on Earth (g = 9.81 m/s²). What is its range (no air drag)?
Conservation in action
A 2 kg ball is dropped from 10 m. Ignoring air drag, what is its speed just before impact? (g = 9.81 m/s²)
Centripetal pull
A 0.5 kg mass swings on a 1 m string at 4 m/s. What centripetal force does the string exert?
Tune the wave
A wave has frequency 50 Hz and wavelength 6 m. What is the wave speed?
Ohm's law
A 12 V battery drives current through a 4 Ω resistor. What is the power dissipated?
Earth–Moon pull
Compute the gravitational force between Earth (5.972e24 kg) and Moon (7.342e22 kg) at 3.844e8 m. Give the exponent of 10 (i.e. answer the integer n where F ≈ a·10ⁿ N, n in N).
Thin lens
An object sits 30 cm in front of a converging lens of focal length 20 cm. Where is the image (cm from lens)?