Aim: What is motion? Do Now: Have you ever seen a race? Describe what occurred during it. Homework: Vocabulary Define: Motion Point of reference distance displacement speed velocity force Textbook: Read pp.440 445 Copy & Answer Questions p.445 # 1, 2, 3 Motion *All matter in the universe is constantly at motion Motion an object is in motion if its position is changing Point of Reference the point by which we use to determine if an object has changed position Distance the length of the route an object travels or moves Displacement the distance between the start and end points and the direction which is traveled Speed how fast an object travels calculated distance divided by time Speed (meters/ sec) = Distance (meters) Time (seconds) Jan 21 9:58 AM Jan 22 10:21 AM Aim: What are forces? 10/13/2010 809 Do Now: What happens if you push on a swinging door? What if you push on a wall? Homework: Create a small poster showing balanced and unbalanced forces. draw in the arrows showing force directions All students: have test signed Jan 23 8:49 AM Oct 13 9:27 AM 1
What is a Force? FORCE = Any push or pull which causes something to move or change its speed or direction Oct 13 9:32 AM Jan 22 2:08 PM Forces can be BALANCED or UNBALANCED Balanced forces are equal in size and opposite in direction Unbalalanced forces are not equal in size and/or opposite in direction. If the forces on an object are UNBALANCED, we say a NET force results & Motion occurs Jan 23 6:26 AM Oct 14 12:32 PM 2
TP: What is gravity 806 11/2/11 Do Now: What are the 2 factors that influence the force of gravity Homework: Complete the Worksheet on Gravity! Front & Back Oct 14 12:01 PM Nov 2 12:15 PM What is Gravity? GRAVITY: An attraction force between all masses Every object in the universe exerts a gravitational attraction to all other objects in the universe The amount of gravitational force depends upon the mass of the objects and the distance between the objects Jan 23 6:28 AM Jan 23 6:29 AM 3
Aim: What is friction? Do Now: 1. If 3 students are able to lift a desk 0.5m off the ground, has there been a balanced or an unbalanced force been applied? Homework Read pp 468 473 Vocab (In back of NB): force, net force, balanced forces, unbalanced forces, friction, P. 1,2,4 Copy & answer in your NB Nov 2 12:32 PM Oct 14 7:00 AM Oct 14 9:17 AM Oct 14 9:26 AM 4
Object Direction Force Do Now: Finish copying 809 Friction Inertia the tendency of an object to resist a change in position Friction a force that resists sliding between two touching surfaces or through air or water slows, and eventually stops an object's motion Static Friction prevents an object from moving when a force is applied Sliding Friction due to the roughness of of two surfaces; the rougher the surface the more friction there is Example: Sandpaper or Ice which has more friction Rolling Friction between a wheel and the ground Example: Walking! the ball of your foot & the ground Oct 13 7:09 AM Oct 14 7:07 AM The greater the mass, the greater the force The greater the distance, the less the force Weight is a measure of the gravitational force between two objects The greater the mass the greater the force (weight) Measured in units called Newtons (N) Acceleration due to gravity = 9.8 m/s/s or 9.8 m/s 2 Jan 23 6:34 AM Jan 23 6:37 AM 5
Air resistance: The force of air exerted on a falling object The air pushes up as gravity pulls down Dependent upon the shape and surface area of the object When the air resistance equals the force of gravity, terminal velocity is reached Terminal velocity is the highest velocity that an object will reach as it falls Jan 23 6:38 AM Jan 23 6:39 AM Speed: The rate of change of position Speed = distance time or = distance time Example: 50 km/hr Velocity: Speed + Direction Example: 50 km/hour North Jan 23 6:40 AM Jan 23 10:49 AM 6
Jan 22 7:05 AM Jan 22 7:06 AM Aim: What is momentum? Do Now: Take out labs from yesterday to be collected Homework: Rd pp. 451 456 P. 456 # 1, 4, 5, 6 Jan 22 7:05 AM Oct 19 7:12 AM 7
Formula first: p = mv p = 10 kg x 5 m/s = 50 kg m/s Change in momentum = + 0.2 kg x 6 m/s 0.2 kg x 6 m/s = +2.4 kg m/s Force_2010.notebook Momentum (p) a measure of how hard it is to stop an object depends on the objects mass (m) and velocity (v) 1. What is the value of the momentum of a 10 kg ball running down a bowling alley at a speed of 5 m/s? Momentum Equation: Momentum (kg x m/s) = mass (kg) x velocity (m/s) p = m. v Think of a ball bouncing off a wall. It leaves the wall at the same speed as before. Let s call going from right to left negative, and going from left to right positive 2.Can you show that the change in momentum is +2mv? 3.The ball has a mass of 200 g, and the value of its velocity throughout remains 6 m/s. What is the change in momentum? Change in momentum = momentum after momentum before. Change in momentum = + mv mv = + 2mv Oct 19 7:17 AM Oct 19 7:31 AM Law of Conservation of momentum The total momentum of objects that collide is the same before and after the colission, as long AS NO OUTSIDE FORCES ACT ON THE OBJECTS (LIKE FRICTION & GRAVITY) Since it is impossible to NOT have friction & gravity, momentum is actually changed. Sometimes the effect is so small it has no measurable effect. Oct 20 9:37 AM Oct 19 7:22 AM 8
Aim: What are the Laws of Motion? Homework: Use pp. 468 473 in text book Define in your vocabulary section: Force Net Force Balanced Force Unbalanced Force Friction Static, sliding & rolling Newton's 1st Law of motion Galileo Jan 21 10:07 AM 9