Physicsmedium · Past Paper
A stone of mass 2 kg is dropped from a tower 20 m high. What is its kinetic energy just before hitting the ground?
A40 J
B200 J
C400 J
D800 J
✓ Correct Answer: C — 400 J
By conservation of energy, KE at bottom = PE at top = mgh = 2 * 10 * 20 = 400 J.
Share this question
More from Physics
- In a step-up transformer, the current in the secondary coil compared to the primary coil is:
- A SONAR device on a ship sends a signal to the ocean floor and receives an echo 4 seconds later. If the speed of sound in water is 1500 m/s, what is the depth of the ocean?
- What is the wavelength of a sound wave with a frequency of 20 Hz in air where the speed of sound is 340 m/s?
- A 100 Watt bulb is used for 10 hours daily. How many 'units' of electricity does it consume in one day?
- A stethoscope works on the principle of: