MotionMotion

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

What is motion anyway?

• Motion is a change in position, which is measured by distance and time.

• Anything moving is in motion

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

What changes motion?

• A force is a push or pull that can change motion.– A force can move an object.– A force can transfer energy to an object.– For example, pushing on a wall doesn’t move

the wall, but energy is being transferred.

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Unbalanced Forces• In order for a force to move an

object, there must be unbalanced forces.

• Like tug of war…the winners are pulling the other team with more force; therefore, the pulling forces are unbalanced.

http://commons.wikimedia.org/wiki/File:Tug_of_war_2.jpg

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

How can unbalanced forces affect objects?

• Unbalanced forces can change the position, speed, or direction of an object.

• Resistance forces (friction or wind) that oppose motion can slow down an object.

• A force in the same direction can cause an object to speed up.

• A force from a different direction can change the object’s direction.

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Balanced Forces

• If we have unbalanced forces, then there must be balanced forces.

• When forces are balancedbalanced, an object’s motion will be constant. It will not change speed or direction.

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Speed• We talk about speed everyday.

• Speed is the distance traveled by a moving object per unit of time.

• Speed affects the energy of an object. The faster it moves, the more kinetic energy it has.

• Speed = distance time

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Calculating Speed

• If I traveled 30 meters in 10 seconds, what was my speed?

o S = D/To 30m/10so 3 m/s

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Kinetic Energy

• The energy of motion

• Objects in motion have kinetic energy.

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Distance

• Distance is a description of how far an object traveled between two points.

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Velocity• Velocity and speed are like fraternal

twins- very similar, but with important differences.

• Velocity is speed in a given direction. – 35 mph NORTH– 4 km/sec EAST

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Which is which?

• 100 m/s right• 1500 km/s • 65 m/s north• 3000 km/s

VelocitySpeedVelocitySpeed

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Acceleration

• Acceleration is the change in velocity.

• It can be a change in speed, direction, or both.

Developed by the Texas Education Service Center Curriculum Collaborative (TESCCC)

Friction

• Friction is a force that opposes motion.• It can be caused by wind, water, surface

texture, etc.• Have you ever ridden down the street on

your bike and felt the wind push against you?

• That’s air resistance!