Forces and Motion Simulation Summary Notes Forces Forces

Forces and Motion Simulation Summary Notes

Forces

Forces �Forces have Magnitude and Direction. 50 N in Each direction �We represent these in diagrams with arrows. �Larger the force the bigger the arrow.

Forces and Motion �When we look at a diagram we can figure out the sum of forces. 50 N in each Direction �Sum of forces = Force applied- friction force. �In other words = Larger force – smaller force.

Forces �If 50 N in each direction the forces are equal then the sum of forces will be 0. The object won’t move. �This is a equal force

Forces � Sum 150 N of forces= Force applied – friction force � What is friction? � Friction- is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other � Which one is resisting movement?

Forces � The 150 N force to the right is bigger then the force to the left. � The object will move to the left. The right force is resisting movement. � Sum of forces- 150 N 50 N=100 N to the left. � This is a Unequal force

Motion

Motion � Important to consider!! � In this simulation FRICTION was NOT taken into consideration. � No friction was acting on the wheels of the skate board

Motion � The heavier the mass of the object the longer it took for the object to reach maximum speed. � Mass- a property of a physical body which determines the strength of its mutual gravitational attraction to other bodies and its resistance to being accelerated by a force.

Friction

Friction �is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. �There are four kinds of friction we are going to talk about. Static Friction, Sliding Friction, Rolling Friction, and Fluid Friction.

Static Friction � Static Friction – occurs when a body is forced to move along a surface but movement does not start. � The magnitude of the friction force is equal or greater than the applied force. No movement occurs.

Sliding (kinetic) Friction �This occurs when the applied force is greater then the frictional force. �This causes the object to move along the surface.

Rolling Friction. � This is what was being ignored in the motion simulation. � Rolling friction is a force that slows down the motion of a rolling object. � Combination of frictional forces at the point of contact with the wheel and the ground/surface.

Fluid friction � Occurs when a body moves in a fluid or air and there exist a resistive force that slows down the motion. � Freely falling skydiver feels a drag force due to air which acts in the upward direction (opposite) of the skydivers motion.

Acceleration

Acceleration � Acceleration - defined as the rate at which an object changes its velocity (speed+direction). An object is accelerating if it is changing its velocity. � Velocity- is simply speed+ direction.

Acceleration � Math makes this easier to understand � Acceleration = Force (N) / Mass(kg) � Acceleration has the units of meters per second squared (m/s 2 )

Newton's Laws of Motion � 1 st Law- Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

Newton's Laws � 2 nd -The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors

Newton's 3 rd law � For every action there is an equal and opposite reaction.