Presentation on theme: "Force, Mass and Motion S8P3 Students will investigate the relationship between force, mass and motion. Determine the relationship between velocity and."— Presentation transcript:
1 Force, Mass and MotionS8P3 Students will investigate the relationship between force, mass and motion.Determine the relationship between velocity and acceleration.Determine the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction.Demonstrate the effect of simple machines on work.
2 VocabularyAcceleration – the rate at which velocity changes. (speed or direction changes = acceleration)Acceleration =Example – Turn left onto another road or going down a hill in a car.Negative Acceleration – acceleration in which velocity decreasesExample – when a car slows downDeceleration - acceleration in which velocity decreasesExample – when a plane slows down to landFinal velocity – starting velocity= m/s/sTime
3 Vocabulary Speed – rate at which an object moves (distance/time) (m/s) Example – how fast a ball is thrown, car drivesVelocity – the speed of an object in a particular direction. (distance/time, direction)Example – The car is driving 5 miles/hour north.Final Velocity – final point at which velocity is measuredExample – when a car stops or passes an ending point.Initial Velocity – beginning point at which velocity is measured.Example – When a car starts or passes a beginning point.
4 VocabularyForce – a push or pull. It has size and direction. (Newton (N))Example – pull open a door, pushing a car door shut.Mass – the amount of matter in an object. (grams (g))Example – ping pong ball verses a marbleMotion – when an object changes position over time when compared with a reference point.Example – running
5 VocabularyFriction – a force that opposes motion between two surfaces that are touching.Rubbing hands together, pushing a box on concreteInertia – tendency of all objects to resist any change in motion.Example – ball will stay in motion unless another force acts upon it like gravity.Gravity – a force of attraction between objects that is due their masses.Example – ball falls to the ground.Distance – the amount of space between two points.Example – my house is 2 miles from your house
6 SpeedHow Fast????Have to know Distance an object moves and Time needed to travel that distanceFormulaAverage Speed = Distance Traveledmeters/secondTime Traveled
7 More about speedMost objects CONSTANTLY change speed, so when you use the formula, it is the average speed.If you drive to school, how often do you go 50 mph the entire way? Never.
8 Velocity Speed of an object in a certain direction 2 cars were traveling at 50 km/sec on the highway for 2 hours. After 2 hours, one car was in Alabama and one car was in Florida. HOW???Opposite Directions! This is why know the direction is important when calculating velocity.
9 More on Velocity It changes when speed OR direction changes You go from 20 mph to 50 mph, you change velocityYou go from 20 mph to 20 mph, but turn left you changed velocity.50 mph North shows velocity Why?
10 AccelerationThe rate at which velocity changes, so… speed or direction have to change for the acceleration to change.Deceleration: slow downChange in speed or direction = (Final V – Initial V / Time)Another word for Initial velocity is starting or original.
11 Examine the table below for the acceleration of a car Examine the table below for the acceleration of a car. You can see the acceleration of the car at any time is 5 m/s/s, so every second, the velocity of the car increases by 5 m/s.Time (second)Velocity (meters per second)15210315420
12 TOTD Give one example of a change in acceleration What info do you need to calculate velocity? (3 things)What is the average speed of an object that travels over 100 meters in 20 seconds?
13 InertiaObjects resist change in motion. If I am standing still, I will stay that way until…. This is called INERTIA Inertia is wearing a seat belt Example: a car is going 50 mph and comes to a sudden stop, you continue moving a 50 mph, unless something stops you… a seat belt or the dashboard.
14 Mass VS InertiaAn object with a large mass has more interia. Changing the motion of an object with a large mass is harder than changing the motion of a smaller object. Which would you rather change the motion of?Moving Car or Rolling Soccer Ball
15 Think about it??? Which would you rather stop falling with your head? Ping pong ball or marbleWhich would you rather pull?Tractor or wagonWhich would you rather swing?Golf club or grand father clock pendulum?
16 Friction Affects the motion of an object A force that opposes motion Friction reduces the speed of an object and releases heat.The amount of friction depends on:Texture of the surfaceWeight of the object being pushed or pulledThe amount of force.
17 Gravity Affects the motion of an object Force of attraction The earth is so large that ALL objects are attracted to itGravity depends onMassDistance
18 Balanced VS Unbalanced forces net force = 0No motionTotal amount of force on an objectUnbalanced forces –net force is greater than (>) 0MotionObject acted on shows movement in one direction.
19 Are these activities balanced or unbalanced forces?
21 Mass The amount of matter in an object. NOT Weight of an object Your mass is the same whether on Mars, Earth or the Moon. Your weight will change.Ping Pong Ball vs. MarbleFeather vs. cotton ballStick vs bamboo
22 MotionA change in the position of an object with respect to time.
23 Simple MachinesLeverInclined PlaneWheel and AxleWedgePulleyScrew
24 WorkThe application of a force to an object to move it a certain distance in the direction of the force.Work = force X distanceW = F X DWork is measured in joules (j)
25 Work you do on a machine is input work Input Vs. OutputWork you do on a machine is input workYou apply a force to the machine and move it through a distanceWork done by the machine is work output.
26 How do Simple Machines make Work Easier? It is a device that makes work easier by changing the size or direction of a force.
27 Inclined Plane Definition How is work made easier Examples (3) A straight, slanted surfaceIt is easier to push an object up a ramp than it is to lift the object straight up.Loading a moving truck, slide, wheel chair ramp
28 Wedge Definition How is work made easier Examples (3) An inclined plane that is wider or thicker at one end than the other.When moved a wedge is used to cut, split, or pry apart objectsDoor wedge to hold open a door, scissors, axe, knife blade
29 Screw Definition How is work made easier Examples (3) An inclined plane that is wrapped around a cylinderForce is applied over a long distance. Longer the threads the more work.Screw, Spiral staircase, top on a bottle
30 lever Definition How is work made easier Examples (3) Made up of a bar that pivots at a fixed point called a fulcrumBased on location of fulcrum and load the work is easier. They apply force to a load.hammer, see-saw, wheelbarrow,
31 Pulley Definition How is work made easier Examples (3) Rope or chain wrapped around a wheelChanges the direction of the effort force and/or multiplying effort.Crane, bike, flag pole and flag, climbing gear
32 Wheel and Axle Definition How is work made easier Examples (3) Consists of two circular objects of different sizes.Gets more force from the effort compared to the distance.Wheelbarrow, doorknob, bike wheel