Motion, Forces, and simple Machines

Andrew Lisbon Tuesday 5/6/2014

Motion

• Motion- the action or process of moving or of changing place or position.

Motion Is Relative

• 1 Motion depends on a reference point • 2 Choosing a reference point • 3 A reference point on earth’s motion• Motion- as observed from or referred to some

material system constituting a frame of reference (as two adjacent walls and floor of a room

Motion is a change in Position

• Distance- one way is to describe your motion is to tell how far you went or the distance you traveled.

Speed

• Speed- is the distance traveled divided by the time it takes to travel the distance. Example

• Average speed equationaverage speed (m/s)= total distance (m) total time (s) d v = t

Velocity

• Changing velocity • Velocity- of an object is the speed of an object

and its direction of motion. If you were walking north at a speed of 2 m/s, your velocity would be 2/s north. If you were walking east at the same speed, your velocity would be 2m/s east.

Acceleration

• Acceleration- is the change in velocity divided by the time needed for the change of occur.

What is a Force

• Forces has size and direction- of the force on the first object is opposite to the direction of the force on the ... For every action, there is an equal (in size) and opposite (in direction) reaction. ... a. ... space is void of air so the rockets have nothing to push off of

• Force- is a push or a pull.

Combining Force

• Forces in the same direction- They are equal in size and opposite in direction. ... When two unbalanced forces are exerted in opposite directions, their combined force is equal to the difference between the two forces and is ... What is the combined force on the barge.

• Forces in the opposite direction • Combining force- to bring into such close

relationship as to obscure individual characters two companies combining forces.

Balanced and Unbalanced Forces

• Balanced forces- if the net force is not on zero, the force on an object are unbalanced force.

• Unbalanced forces- the force on the dresser were unbalanced when you both pushed on the dresser.

Unbalanced Forces cause motion to change

• Unbalanced forces cause change in speed- Unlike balanced forces, we say unbalanced forces when two forces acting on an ... What is a force ... Unbalanced forces causes can cause a moving object to change direction Unbalanced forces make the wagon in the diagram speed up.

• Unbalanced forces cause change in direction- moving object to change direction Unbalanced forces make the wagon in the diagram speed up.

Inertia

• Inertia and mass- the more mass an in object more inertia is harder to change.

• Inertia- is the tendency of an object to resist a change in its motion. Because of inertia, the tendency for an object that is not a moving is to stay and rest.

Contact Forces

• The size and direction of friction- like all forces,

friction has a the same size and force and a direction

• Air resistance • Contact force- the force exerted by your hands on

the dresser is a contact force because your hand had to touch it.

• Friction- is a force that oppose the relative motion of two surface that are contact.

Non-contact Forces

• Non-contact force- you might used a magnet to pick up objects such as paper clips. Suppose you place a paper clip on your desktop and slowly bring one end of a bar of the magnet close to it.

Gravity

• 1 Gravity depends on mass and distance

• 2 Gravity- is the pull that every object always exerts on every object due to their masses.

Mass and Weight

• You weight the same thing as your mass however, weight and mass are different your mass is the amount of matter in your recall that mass is measured in kilograms.

What is a machine

• Simple machine- is a machine that uses only one movement to do work.

Making Work Easier

• Input work and output work- when a machine is used, the input force and the output force do work.

• Mechanical advantage- of s machine equals the output force divided by the input force.

The Pulley

• Pulley- is an object like a wheel, that has a groove with a rope or cable running through it.

The Lever

• The wheel and axle- try turning a doorknob by holding the narrow base of the knob.

• Lever- is a rod or plank that pivots about a fixed point called the fulcrum.

The Inclined plane

• The Wedge- when you take a bite out of a moving inclined plane with one or two slopping sides.

• The Screw- a road going up a mountain usually wraps around the mountain.

• Inclined plane- is a flat, sloped surface.