Review of Grade 9 Motion and Vectors new

Review of Grade 9 Motion and Vectors (new) Speed Velocity Acc eler atio n Distance - Displacement

Vectors A A Vectors have size and direction, but no place head A A A tail A

A Two vectors are equal if they have the same magnitude and the same direction B A=B Physical quantities can be split into: SCALARS: Have size (magnitude only) e. g. time, mass, speed, distance, voltage, energy VECTORS: Have size and direction e. g. velocity, acceleration, force, displacement

Identify these quantities as scalars or vectors Question 1 2 3 QUANTITY distance circumference speed 4 5 velocity displacement 6 7 8 9 force acceleration time energy 10 momentum Scalar Vector Click q for answers

Identify these quantities as scalars or vectors Question 1 2 3 QUANTITY distance circumference speed Scalar S S S Vector 4 velocity V 5 6 7 8 9 displacement force acceleration time energy V V V 10 momentum S S S V

Vectors and Scalars Vector Quantities – have magnitude and direction Ex: displacement: I walked 20 meters west Ex: velocity: 60 miles per hour north Vector – an arrow drawn to scale used to represent a vector quantity 30 m/s north Ex: 60 m/s east 30 m/s east Scalar Quantities – have magnitude only, no direction

http: //youtu. be/A 05 n 32 Bl 0 a. Y

The symbol Δ refers to finding a change in a set of values (a final state – an initial state). eg Δv means vf – vi Cup of coffee… Ti = 18°C Tf = 98. 5°C ΔT = ? Game of tennis …

Distance - Displacement A model train travels around the track shown below. The table shows its distance and displacement at various stages of the journey around the track. At B At C At D Back at A Distance travelled (m) Displacement from Start (m) 2 4 6 8 2 north 8 northeast 2 east 0

Speed V, units ms-1 scalar

Velocity V, units ms-1, vector

Ex: Walking a dog Which one has greater average velocity? ? We need another way to describe motion: Not a vector! (It’s a scalar) Web Link: Speed vs Velocity

v Instantaneous Speed - speed at any given instant in time. v Average Speed - average of all instantaneous speeds; found simply by a distance/time. (km)

*Acceleration is a Vector* Usually: +a means speeding up -a means slowing down But Sometimes: -a means speeding up +a means slowing down -x +x Here’s the rule: If v and a have the same sign : it’s speeding up If v and a have opposite signs : it’s slowing down

Acceleration ms-2 a, units ms-2 scalar or vector!