Page 1 1 Science 10 – Motion and Forces. Page 2 Big Ideas of Unit 1.0 Explore motion-related...

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Science 10 – Motion and Forces

Big Ideas of Unit

• 1.0 Explore motion-related technologies• 2.0 Observe and describe the motion of everyday

objects • 3.0 Investigate the relationship among distance, time,

and speed for objects that undergo uniform motion • 4.0 Investigate the relationship among speed, time, and

acceleration for objects that undergo uniformly accelerated motion

• 5.0 Analyze graphically and mathematically the relationship among distance, speed, time, and acceleration for objects that undergo simple linear motion or uniformly accelerated motion

What is Motion???

• List some types of motion?

• What is the most extreme type of motion that you can think of?

1.0 Explore motion-related technologies

I Wonder about Motion??

Example questions might include:

• What is the effect of waxing skis on the performance of skis?

• Why do speed skaters wear different types of skates than figure skaters?

• What is the effect of different wheel sizes on the performance of a vehicle (bicycle, car, wheelchair,

etc.)?

• How long can a human keep accelerating?

• What is the effect of wearing flippers on swimming?

• Why have speed limits been established on public roads?

Instruments of Motion

• Explore a specific motion-related technology such as a personal transportation device (e.g., bicycle, snowmobile, automobile, motorcycle, skateboard, kayak, snowshoe, or wheelchair)

• Trace its evolution, describe the historical development of the technology and the roles of science and technology in the development of that technology.

• Make a sign, brochure or 1 page paper that promotes your motion related technology

• You will have today and tomorrow to research and complete the assignment so USE YOUR TIME WISELY!!!

• Be creative, use graphics and be sure to include the proper information

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Motion

• Motion is the change of positionEx. You are driving in your car. You are in

motion relative to the earth, but not with respect to your car.

• Uniform motion is the simplest type (straight path)

• One must distinguish between the two terms below:

SPEED rate of motion

VELOCITY rate of motion with a direction

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Speed (velocity) = distance traveled OR v = d

interval of time t

Problems: Let us suppose that a car is traveling at 20m/s.

1) What would be the position of the car after 5s?

2) Calculate the distance traveled after 20s and after 120s.

3) Calculate the time required to travel 140m.

Assignment

• Speed trial lab- finish today!• Or• Bubblegum physics- finish today!!

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Distance-Time Graphs for Uniform Motion

Problem If we prepare a table to show the position of a car at 5 second intervals, then we can plot a graph.

t(s) 0 5 10 15 20 25 30 35 40 45 50

d(m)

0 100

200

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1000

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Graph of Distance vs. Time

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0 5 10 15 20 25 30 35 40 45 50

Time (s)

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tan

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The distance-time graph for uniform speed is a straight line (constant slope)

1. How far would the car travel during a 20 second interval?

2. How far would it travel between the 25s and 50s interval?

3. How long would it take the car to travel 450m?

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Sample Problem 2 the motion of two cars A and B is represented by the following graph. What can we learn about the motion of the cars from the graph?


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Car A

Car B

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One line climbs more steeply than the other. Car A, moves a greater distance within an interval of time. Car A must be traveling faster than car B.

• Slope (Steepness)y the change in vertical directionx the change in horizontal directionslope = y = rise = y2 – y1 x run x2 – x1*higher speeds give greater slopes.

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Let’s find the slope of both of the lines from the previous graph.

Car A Car B

If you look close, slope = d/tRecall, v = d/t the slope is telling us the speed of the

object that is moving.

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In this graph, the lines are parallel (equally steep). Vehicle A and B are starting from different positions, but their speeds are the same.


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Assignment

• Domino Dash

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Speed and Direction

This graph represents an object traveling to a certain point, stopping for a while, then returning to its initial position again.


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0 5 10 15 20 25 30 35 40 45

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Calculate the slope of the 3 intervals: A, B, and C.

Interval A

Interval B

Interval C

*We see that the slope is negative for interval C indicating that it is traveling in the opposite direction. The object has returned to its original starting position.

Average Speed

If the slope of a graph changes, the speed of the object has also changed. Non-uniform motion is the change in speed or direction, or both. A roller coaster is a good example.

When an object’s speed changes several times in a trip, the average speed can be calculated by:

Average Speed = total distance traveled OR vav= d total time for trip t

Example:

A delivery person travels from Saskatoon to Warman to drop off a parcel. It takes 15 minutes to travel to Warman, 10 minutes to drop off the parcel, and then 20 minutes to get back. What is the speed of the truck to get there? What is the speed of the truck on the way back? What is the average speed of the trip? (The distance from Saskatoon to Warman is 25km)

assignment

• Describing position-time graphs• Uniform motion• Velocity from position-time graphs

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