 # Speed, Distance, & Time Practice

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Speed, Distance, & Time Practice
TOC FOR 11/2

STARTER (write this under the date Nov 1)
1. Pick a vocabulary word and KISS definition Warm Up On Left hand side, under date 2. Circle your answer and Justify your choice

MOTION An objects change in position relative to a reference point over a period of time. REFERENCE POINT – A place or object that can be used to determine if an object is in motion.

SPEED The rate at which an object moves.
Depends on the distance traveled and the time taken to travel the distance. D / T

SPEED EXAMPLE A hockey puck slides along the ice for 3 s before crossing the goal line 6 m away. What is the average speed of the puck before it crossed the goal line? S = D / T S = 6 m / 3 s S = 2 m/s

Go over more examples on the board

III. Application Worksheet goes here once graded!

IV. Connection Today your boss informed you that you have a meeting tomorrow morning at 8:00 am. Cool…BUT, it’s in Waco. WACO!! That’s 168 miles away. You don’t know how long it will take to get there, but the speed limit is 70 mph. You don’t want to get a ticket, so what time will you have to leave??

Hmmmm… Speed = 70mph Distance = 168 mi T = D/T Time = 168/70 = 2.4 hours ** (2.4 is not 2 hours and 40 minutes!!!)*** What time do I leave?

2.4 is almost 2 ½ hours. .4 = 4/10 Make a proportion! 4/10 = x/60 X = 24 It is actually 2 hours and 24 minutes. I would need to leave at 5:36!

V. Ending Describe why it’s important to calculate speed (write 4-5 sentences).

VELOCITY & ACCELERATION
TOC FOR 11/9

Focus Grab your notebook and complete the quiz Turn in once complete

Notes on Velocity and Acceleration

VELOCITY Speed (D/T) in a given DIRECTION.

VELOCITY EXAMPLE What would your velocity be if you traveled 1 km east in 0.5 h? V = D T V = 1 km 0.5 h V = 2 km/h East Direction East

ACCELERATION The rate of change in velocity.
Can be speeding up, slowing down or changing directions

CALCULATING ACCELERATION
Acceleration = Final Velocity – Initial Velocity Time

ACCELERATION EXAMPLE Example: Riding your skateboard, it takes you 12 s to accelerate from 2 m/s to 8 m/s. What is your acceleration? A = 8 m/s – 2 m/s 12 s A = 6 m/s A = 0.5 m/s2

Example: Riding your skateboard, it takes you 12 s to accelerate from 8 m/s to 2 m/s. What is your acceleration? A = 2 m/s – 8 m/s 12 s A = - 6 m/s A = m/s2 (slowing down)

III. Application Worksheet goes here once graded!

IV. Connection 1. Find the velocity in m/hr of a runner who runs exactly 100m north in exactly 2 hours. 2. What would his acceleration be if he started at that velocity, but ended with a velocity of 75m/hr?

V = D/T D= 100m T= 2 hours V = 100/2 = 50 m/hr north
Acceleration: 75-50 2 25/2 = 12.5 m/s squared

Compare and Contrast speed, velocity and acceleration (write 4-5 sentences).

FORCE FORCES CAUSE ACCELERATION! Push or pull Affects motion:
Set the object in motion Stop its motion Change the speed and direction of its motion FORCES CAUSE ACCELERATION!

FORCE FACTS Measured in Newtons (N) Act in pairs
Act in a particular direction

Push or Pull? Changing speed, direction or both?

TWO THINGS AFFECTING MOTION
How strong the forces are The direction of the forces

NET FORCE When more than one force acts on an object, the forces combine to form a net force. Same direction – ADD Opposite directions - SUBTRACT

BALANCED FORCES Opposite in direction & equal in size
NO change in movement 2000 N 2000 N 2000 N – 2000 N = 0 N

UNBALANCED FORCES Not always opposite and not equal in size
Causes movement 5000 N GRAVITY 1000 N RESISTANCE AIR 5000 N – 1000 N = 4000 N

EXAMPLE The forces shown above are PUSHING / PULLING forces.
The forces above are WORKING TOGETHER / OPPOSITE FORCES? The forces are BALANCED/ UNBALANCED. The forces DO / DO NOT balance. The stronger force is pulling to the RIGHT / LEFT. The weaker force is pulling to the RIGHT / LEFT. Motion is to the RIGHT / LEFT. 100 N 200 N

TYPES OF FORCES Buoyant Force Magnetic Force Electrical Force
Gravitational Force Elastic Force Centripetal Force Frictional Force

FRICTION A force opposing (going against) motion
Brings an object to rest

FOUR TYPES OF FRICTION Sliding Friction – 2 solid surfaces sliding over each other *** Opposes motion the most! Rolling Friction – Object rolling over a surface Fluid Friction – Object moves through a fluid (liquid or a gas) Static Friction – The force of 2 surfaces in contact but does not cause movement

FOUR TYPES OF FRICTION

NEWTON’S 3 LAWS 1ST LAW – When forces are balanced, an object at rest will stay at rest and an object in motion will stay in motion at a constant velocity

2ND LAW – Force = Mass x Acceleration

3RD LAW – For every action, there is an equal and opposite reaction

GRAVITY A force of pull between objects Increases as mass increases
Increase as distance decreases The measure of gravity IS an object’s weight