Physics

• W = mg, where m is the mass of the body in kilograms and g is the gravitational field strength in meters per second squared.
• A stationary object is represented by a horizontal line on a graph of displacement (y axis) against time (x axis).
• An object with constant velocity is represented by a line with a constant gradient on a graph of displacement (y axis) against time (x axis).
• Acceleration or deceleration is represented by a curved line on a graph of displacement (y axis) against time (x axis).
• An object with a constant velocity is represented by a horizontal line on a graph of velocity (y axis) against time (x axis).
• The constant acceleration of the object for a positive gradient or constant deceleration for negative gradient is represented by a line with a constant gradient on a graph of velocity (y axis) against time (x axis).
• The area under a velocity-time and acceleration-time graph represents the displacement of the object and the change in velocity respectively.
• The terminal velocity of an object can be determined using light gates by timing when each of the two beams are broken by the object and the time difference (with a number of repeats done to improve the accuracy) combined with the known distance between the light gates are used to find the velocity.
• A scalar quantity is a quantity that only has magnitude not direction.
• A vector quantity is a quantity that has magnitude as well as direction.
• Acceleration is a vector quantity.
• Mass is a scalar quantity.
• In projectile motion, the horizontal or vertical component of velocity is constant.
• The vertical acceleration in projectile motion is equal to the gravitational field strength (g).
• Gravitational field strength can be determined using the equation G = F / m, where F is the force on a body in a gravitational field/N and m is the mass of the body/kg.
• Kinetic Energy is the energy associated with the motion of an object with mass, and its SI base unit is kg m^2 s^-2.
• By considering a closed system where an object is moving up and down, a formula for the velocity of an object in a gravitational field can be derived.
• Gravitational Potential Energy is the energy stored by an object at a point in a gravitational field, and its SI base unit is N m^2.
• Elastic Potential Energy is the energy stored by an object as a result of a reversible change in an object’s shape, and its SI base unit is J.
• Power is the energy transferred per unit time, and its base unit is J/s.
• A moment is a turning force, and its equation is Moment = force x perpendicular distance from the object.
• The total energy in a closed system will always remain the same.
• All initial Gravitational Potential Energy is converted to Kinetic Energy as the object falls, and this Kinetic Energy is converted back to Gravitational Potential Energy as it rises.
• For an object in equilibrium, the sum of the clockwise moments will equal the sum of the anticlockwise moments.
• The centre of gravity of a uniform object is at its geometrical centre.
• The principle of conservation of energy states that energy cannot be created or destroyed, only transferred into other forms of energy.
• The work done is a measurement of energy and its units are joules with SI base unit kg m^2 s^-2.
• The forces acting on a free-falling skydiver can be described with diagrams.
• Impulse, the change in momentum, is represented by the area underneath a force time graph.
• The work done is defined as the product of the magnitude of the force and distance moved by the object in the direction of the force.
• The equation for momentum is momentum = mass × velocity.
• Linear momentum is conserved in all collisions.
• Newton’s third law states that every action force has an equal and opposite reaction force.
• The rate of change of momentum can also be described as force.
• In an inelastic collision, the kinetic energy at the end is not equal to the kinetic energy at the start.
• Newton’s second law, F = ma, states that force is equal to mass times acceleration.
• The rate of work done is equal to power.
• Newton’s first law states that an object stays moving at a constant velocity unless a force acts upon it.
• In an elastic collision, the kinetic energy before is equal to the kinetic energy afterwards.
• At the point of breaking stress, the atoms of the material separate completely, causing it to break.