Experiment Design
What is the independent variable in an experiment?
Variable changed on purpose
Define acceleration.
Rate of change of velocity
What is the formula for momentum?
Mass × velocity
What is thermal energy?
Heat energy (total kinetic energy of thermal motion of particles and potential energy of their intermolecular interactions).
What is the formula linking voltage, current and resistance? How is it called?
V = IR, Ohm's Law
Name two control variables in a simple pendulum experiment.
String length, mass, angle
State Newton’s First Law.
Objects stay at rest/motion unless force acts
A 2 kg object moves at 3 m/s. What is its momentum?
6 kg·m/s
Name the three types of heat transfer.
Conduction, convection, radiation
What is the current in a 6 Ω resistor if 12 V is applied?
I = 2 A
Why is it important to take multiple measurements?
To increase reliability & reduce random error
What two forces act on a falling object?
Weight (gravity) & air resistance
State the law of conservation of momentum.
Total momentum before = after if no external forces act on object
What is specific heat capacity?
Energy to change temp of 1 kg by 1°C
A 60 W bulb is connected to a 230 V supply. What is the current?
I = P/V = 0.26 A
What does a non-linear graph tell us about a physical relationship?
The variables are not directly proportional
A ball is thrown upward at 15 m/s. How long until it reaches its highest point? (g = 10 m/s²)
1.5 seconds
Two trolleys (mass = 1 kg and 2 kg) collide and stick together. If the first was moving at 6 m/s and the second was stationary, what is their final velocity?
2 m/s
2 kg of water is heated from 20°C to 80°C. How much energy is required? (c = 4200 J/kg°C)
Q = 4200×2×60 = 504,000 J
Explain why fuses are important in electrical circuits.
Prevent overheating/damage
How would you control variables in an experiment investigating how friction affects acceleration on a ramp?
Same surface, same angle, same mass
A 5 kg object experiences a net force of 20 N. How far does it travel in 4 seconds from rest?
64 m
A 0.5 kg object is dropped from 5 m. Describe change in it's mechanical energy while falling downwards and find it's final speed before hitting the ground? (Ignore air resistance, g = 10 m/s²).
Kinetic increases, potential decreases, 10 m/s
A 0.2 kg block of ice at 0°C melts using 67,000 J of energy. What is the specific latent heat of fusion?
Lf = 67,000 ÷ 0.2 = 335,000 J/kg
In a parallel circuit, one bulb goes out. What happens to the others?
They stay lit and be slightly less brighter