- Scalar: magnitude e.g. mass, energy, speed, distance.
- Vector: magnitude and direction e.g. force, velocity, displacement.
- Average speed = distance travelled/ time taken.
- Acceleration = change in velocity/ time taken.
- F=ma
- W=mg
- Force (N), m: mass (kg), a: acceleration (m/s2). W: weight (N), g: 9.8 m/s2)
- Weight is force due to gravity, so can be different on the moon.
- Mass doesn't change but g and weight can.
- Resultant force: the sum of all forces acting on an object.
- Newton’s 1st Law: if there is a resultant force, an object will accelerate or decelerate. If not, the object will remain stationary or at constant speed.
- Newton’s 2nd Law: F=ma
- Newton’s 3rd Law: when two objects interact, they exert an equal and opposite force on each other.
- Terminal velocity: first, the car would accelerate because the driving force is bigger than the resisting force. Then, the resisting force increases. Eventually, driving force = resistance, so the car will continue at a constant speed.
- We can use more than one force to stretch, bend or compress an object.
- F: Force (N), k: spring constant (N/m), e: extension (m)
- Hooke's Law: extension is directly proportional to the force applied, until the limit of proportionality.
- Elastic potential energy: equation given.
- Elastic deformation: the object will return to its original shape and length after the forces are removed
- Plastic deformation: the object will not return to its original shape.