Forces

• What is a force?


  a push or a pull on an object when it interacts with another object
• A contact force can only be exerted if the two objects are touching
• A non-contact force is a force that does not require physical contact between two objects.
• contact forces are thrust, tension, upthrust, friction, gravity and normal contact force
• Force is measured in Newtons
• non-contact forces are gravity, magnetic and eletrostatic
• speed= distance/time (m/s)
• air resistance, water resistance and friction all go against the movement of the object
• Drag is the force that opposes the motion of an object
• Friction is exerted when objects try to slide over each other
• Water resistance is exerted when an object moves through water
• air resistance is exerted when an object moves through air
• lift is exerted on an airplane in an upwards direction
• Gravity is exerted on any object with a mass
• Magnetic force is exerted on magnetic materials or magnets
• velocity: the speed of something in a given direction
• Weight acts in a down direction however if there is more than 1 point of contact the total weight will spread out accordingly
• normal contact force occurs when an object exerts its force on a second object and the second object will exert a force equal to object one but in the other direction
• A balanced force is when a force in the opposite direction is equal to the force in the other direction
• An unbalanced force is when a force in the opposite direction is not equal to the force in the other direction
• pressure is related to how spread out a force is over an area
• Pressure = Force / Area
• Friction always goes in the opposite direction.
• To reduce friction you can use lubricants
• The steeper the gradient the faster the object
• the shallower the gradient the slower the object
• vaccum is the absence of particles
• the higher the drag the less the motion
• the less the drag the more motion
• Constant speed is when the thrust and air resistance are the same however accelaration is when the thrust is higher than the air resistance
• The resultant force is the overall force acting on an object, if they are balanced the resulant force will be 0
• normal contact force means that the object is in contact with the surface and the force is equal to the weight of the object
• Newtons Law is When an object imposes its force onto the object the other object imposes an equal amount of force in the other direction
• weight = mass x gravitational field strength
• the difference between weight and mass is mass is the amount of matter in an object and weight is the force of gravity acting on an object
• gravity is the force of attraction between two objects with mass.
• weight is the force acting on an object due to gravity