Physics (Motion)

• A balanced force is two forces equal in size and opposite in direction
• An unbalanced force is two or more forces that are unequal in size and direction and therefore change an object's speed, direction or shape
• A force is a push, pull or twist on an object that causes it to move or change its shape.
• Distance is the amount of space between two points on a line or surface.
• Displacement is distance with a particular direction.
• The SI unit for velocity is metres per second (m/s)
• A vector quantity is a quantity that has both magnitude and direction.
• A scalar quantity is a quantity that only has magnitude.
• magnitude is the distance or quantity
• speed is how fast something moves, but not which way its moving
• velocity is speed with direction
• acceleration is change in velocity over time
• Newton's first law states that an object at rest will remain at rest unless acted upon by an unbalanced force.
• newton's second law is that force = mass x acceleration
• newtons third law is every action has an equal and opposite reaction
• when there is a horizontal on a acceleration time graph, it means the object is traveling at a constant velocity
• acceleration is calculated by final velocity-initial velocity/time
• the equation for distance traveled is average speed x time
• to calculate time use the distance and divide it by average speed.
• average speed is total distance divided by total time
• velocity is equal to the rate of displacement over time
• A horizontal line on a displacement/distance time graph means that the object is stationary.
• The gradient of a displacement/distance time graph represents velocity.
• On a ticker timer, if the dots start close together and then spread out, it means that the object is accelerating
• On a ticker timer, if the dots start spread out and then become closer together, then the object is decelerating
• On a ticker timer, if the dots are evenly spread out, the object is traveling at a constant speed
• when there is a line going down on a distance/displacement time graph, the object is moving towards the starting point.
• On a displacement/distance-time graph, if the line is going up, then the object is moving away from the starting point.
• the steeper the line on a graph is, the faster the object is moving
• an example of newtons first law is one's body movement to the side when a car makes a sharp turn.
• an example of Newton's second law is riding a bicycle because the mass is you on the bike and the force comes from pedalling.
• an example of Newton's third law is when you jump, your legs apply a force to the ground and the ground applies and equal and opposite reaction force that propels you into the air.  
• weight is the force exerted on a body by gravity
• mass is the amount of matter in an object.
• acceleration is measured through m/s/s or ms-2