Forces 1 What is force? What is an example of force?
Forces 2 Force is simply defined as a push or a pull. Force is described by it’s magnitude (strength) and by the direction in which it acts. The SI unit of measure for the magnitude of a force is Newton (N)
Forces 3 The combination of all forces acting on an object is referred to as the net force. ALWAYS SHOW THE DIRECTION OF ALL FORCES!!!!!!
Forces 4 When two forces are acting in the same direction, they produce a larger net force. (add, both #s are positive) When two forces are acting in opposite directions, they produce a net force in the direction of the larger force. Equal opposite forces cancel out and produce no net force. (no movement)
Friction 1 Friction is a force that two surfaces exert on each other when they rub against each other. If there weren’t friction (like in space) objects would just keep moving until they ran into something.
Friction 2 Strength of friction depends on two things: Types of surfaces involved How hard the surfaces push together
Friction 3 Static Friction is the friction that acts on an object that is not in motion. Examples? Sliding Friction is friction that acts when two solid surfaces slide over each other. Examples?
Friction 4 Rolling Friction is the friction acting when an object is rolling. Rolling friction is less than sliding friction. Examples? Fluid Friction is the friction that occurs when a solid object moves through a fluid and is less than sliding friction. Examples?
Gravity 1 What is gravity? Gravity is a force that pulls objects toward each other. Gravity acts everywhere in the universe- not just Earth!
Gravity 2 The force of gravity increases between objects with greater mass and decreases with greater distance. Make sense? Examples?
Gravity 3 Gravity and Weight- remember: Weight is a reflection of the gravitational pull on an object. Formula for calculating weight is… Weight = Mass x Acceleration from Gravity
Gravity 4 Gravity and motion! What goes up, must come down. Free Fall is when the force of only gravity is causing an object to accelerate in a downward direction. These objects will accelerate at 9.8m/s2 (This means that the speed will increase by 9.8 m/s every second. WOW!)
Gravity 5 Air Resistance is an upward force that acts on objects as they fall through the air. The larger the surface area, the more air resistance, the slower the object falls. Example: Leaf vs. a ball
Gravity 6 Projectile Motion is the motion an object experiences when it’s been thrown. Objects thrown horizontally will land at the same time as an object dropped if released at the same time. (Gravity acts on both of them).
Elastic Forces 1 Something is considered to be elastic if it returns to it’s original shape after it’s squeezed or stretched. Compression is the elastic force that squeezes or pushes matter together. Tension is the elastic force that stretches or pulls matter apart.