Biking for a Greener PlanetBiking for a Greener Planet

Section 1: Forces and MotionSection 1: Forces and Motion

Read Textbook pages 405 – 409Read Textbook pages 405 – 409 Answer Memory Check questions page 409 Answer Memory Check questions page 409

Types of MotionTypes of Motion

There are four categories of Motion:There are four categories of Motion:– Rectilinear MotionRectilinear Motion– Alternating MotionAlternating Motion– Circular MotionCircular Motion– Oscillatory MotionOscillatory Motion

Rectilinear MotionRectilinear Motion

Motion in a straight lineMotion in a straight line

Example:Example: Running or driving in one directionRunning or driving in one direction

Alternating MotionAlternating Motion

A rectilinear motion that occurs regularly in A rectilinear motion that occurs regularly in one direction and then the other one direction and then the other

Example:Example:

-Yo-yo-Yo-yo

-Electric -Electric knifeknife

Circular MotionCircular Motion

Motion that has a circular or curved pathMotion that has a circular or curved path

Examples:Examples: Ferris Wheel, Orbiting planet, Race car in a Ferris Wheel, Orbiting planet, Race car in a

turnturn

Oscillatory MotionOscillatory Motion

A back and forth motion around a central A back and forth motion around a central pointpoint

Examples:Examples: Rocking chairRocking chair

PendulumPendulum See-sawSee-saw

Force: the Trigger of MotionForce: the Trigger of Motion

Motion cannot spontaneously occur, it Motion cannot spontaneously occur, it requires a trigger.requires a trigger.

This trigger is described as a This trigger is described as a forceforce A A ForceForce is is any influence that causes a any influence that causes a

body to undergo a change in speed, body to undergo a change in speed, direction or shape.direction or shape.

Types of ForcesTypes of Forces

Gravitational Force:Gravitational Force: The force that pulls The force that pulls objects towards the centre of the earth. The objects towards the centre of the earth. The greater the mass of the object, the more greater the mass of the object, the more strongly it is pulledstrongly it is pulled

FrictionFriction: The force that slows down to : The force that slows down to bodies in contactbodies in contact

Type of Type of ForceForce DescriptionDescription DiagramDiagram ExampleExample

Flexion Flexion ForceForce

When a gymnast presses or pulls on the When a gymnast presses or pulls on the bar, her weight applies a flexion force. The bar, her weight applies a flexion force. The bar is likely to bend under the effect of the bar is likely to bend under the effect of the force.force.

Tension Tension ForceForce

When you pull an object in one direction to When you pull an object in one direction to move it, that is tension. A person pulling a move it, that is tension. A person pulling a rope, for instance, exerts tension on it.rope, for instance, exerts tension on it.

Compression Compression ForceForce

Compression is the opposite of tension. It Compression is the opposite of tension. It is a force applied to compress an object. is a force applied to compress an object. When you squeeze a sponge, for instance, When you squeeze a sponge, for instance, you exert compression force.you exert compression force.

Torsion Torsion ForceForce

When you screw on or unscrew a lid, you When you screw on or unscrew a lid, you apply a torsion force. The two objects, lid apply a torsion force. The two objects, lid and jar, turn in opposite directions.and jar, turn in opposite directions.

Shearing Shearing ForceForce

If you pull the corners of a metal sheet in If you pull the corners of a metal sheet in opposite directions, it is likely to break. It opposite directions, it is likely to break. It will shear or tearwill shear or tear

QuestionsQuestions

Which types of force are used in the Which types of force are used in the following situations:following situations:– A) I take a tissue from a box of tissuesA) I take a tissue from a box of tissues– B) I sit on a chairB) I sit on a chair– C) I wring out a wet towelC) I wring out a wet towel– D) I tear a piece of paperD) I tear a piece of paper– E) I press a button on my calculatorE) I press a button on my calculator

Write down the questions and your answers Write down the questions and your answers and hand them in before leaving.and hand them in before leaving.