Describing Motion Warm Up Test Review Test 3

Describing Motion

Warm Up

Test Review � Test 3 = Questions 1, 2, 11, 12, 13, 14, 15, 16 › 8 Total › 12. 5 points a piece � Test 4 = All the other question › 17 Total › 5. 8 points a piece

Speed, Velocity, Acceleration � “Find Someone Who” can tell you what speed, velocity, and acceleration are. › You must locate three different peers to tell you what they think these terms mean and record the answers in the “What we think” row of the document. › You are expected to answer as well as ask. › It’s OK to be wrong but your must have and answer › The student who answers needs to sign his/her name next to their answer. � 2 minute time limit per word

Speed, Velocity, Acceleration � Now list an “A” for agree or a “D” for disagree next to the definitions � Turn to your shoulder partner and explain why they agree or disagree with the definitions. › You have 2 ½ minutes › GO

Speed, Velocity, Acceleration � Update your handouts by recording the scientific definitions of speed, velocity, and acceleration in the “What We Know” row of their handouts. � The Power. Point will instruct you to record examples as they complete their notes on the handout.

Speed � The distance an object travels in a certain amount of time. › Average speed – Total distance divided by total time › Constant speed - Speed that does not change � On your paper, describe an example of an object at a constant speed.

What is the formula for calculating speed? Speed equals distance divided by time.

Let’s Practice Calculating Speed � On the side of your paper, calculate this problem. Make sure you show all work! A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the football player running?

Check Your Work A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast was the football player running? › Speed = Distance ÷ Time › Speed = 100 m ÷ 20 s › Speed = 5 m/s Remember to label the UNITS!!

Velocity � An object’s speed and direction at a given time › The wind is blowing 65 km/hr from the North. � On your paper, describe an example of velocity.

Acceleration A change in the direction or speed (velocity) of an object over time – which may be: › A change in speed �Starting �Stopping �Speeding up (positive acceleration) �Slowing down (negative acceleration) › A change in direction � Acceleration is caused by unbalanced forces. � On your paper, describe an example of an object accelerating. �

Speed, Velocity, Acceleration � How does your “What We Think” section compare to your “What We Know” section? � Does anyone notice any differences in the meaning of the three terms? Explain. › Speed is distance/time, velocity is speed with a direction, and acceleration is a change in speed and/or direction.

Speed, Velocity, Acceleration � The terms we have noted are extremely important in our upcoming unit of study. Be prepared to refer back to them often. � Highlight, circle, or underline the key points

Warm Up

Video � http: //www. youtube. com/watch? v=DRb 5 PSx Jer. M

Calculating and Graphing Speed � Title the next blank page Calculating and Graphing Speed You are going to draw 5 easy graph and interpret the speed

Interpret the Graph Below: The graph shows an object which is not moving (at rest). The distance stays the same as time goes by because it is not moving.

Interpret the Graph Below: The graph shows that the objects distance increases as time passes. The object is moving and so it has velocity. The straight line shows it is a constant (not changing).

Interpret the Graph Below: Just like the previous graph, this graph shows an object moving with constant velocity.

Interpret the Graph Below: The curve, in the graph, shows that the object’s velocity is changing as time passes. This is acceleration.

Interpret the Graph Below: In the first part of the graph, the object is moving with constant velocity. In the second part of the graph, the object is at rest (not moving). In the third part, the object is again moving with constant velocity.

Calculating and Graphing Speed � LAB instructions � Everyone is always recording � Group Roles (you will rotate jobs) › › › Roller Timer 1 Timer 2 Timer 3 Director �Says Start and Stop �Is in Charge

Warm Up

Calculating and Graphing Speed � � Continue the lab Group Roles (you will rotate jobs) › › › � Roller Timer 1 Timer 2 Timer 3 Director When you are finished sit back at your desk and complete the graph and the questions › Work together › Turn in when you are finished › Use COLOR on the graph

Warm Up � � Directions: 1. Read the following scenario. 2. Calculate the average speed. 3. Briefly describe all points of acceleration and explain. � A female cheetah left her cubs to hunt for food. She sprinted 30 m away from her den in two seconds. Next, she turned around and traveled 10 meters back toward her den in three seconds. She suddenly stopped and listened intently for two seconds. Then, she traveled 40 meters away from her den in four seconds.

Card Sort � With your face partner, sort the cards into 3 groups

Story Graphs � With your groups, write a 10 sentence story using 2 of the four graphs. � Your story must include: › › › › The average speed Acceleration Main Character Plot Be creative 10 pictures Use two i. Pad Be prepared to share

Warm Up � Write Tug of War on your warm up � Open Tug of War Handout in e. Backpack

Warm Up

Change the Motion of an Object � Open Change the Motion of an Object in ebackpack › You will answer the questions ON THE FIRST PAGE as you complete the lab � Using the object that I give you make it accelerate AT YOUR DESK!!!!!! � Make it stop, start, speed up, slow down, and change direction

� Volunteer � Pass to Share out the laminated paper

Change the Motion of an Object � With your should partner look at the handout. � Describe the motion of the object. › Such as: left, right, up, down � Then explain to your partner why your think the object will move in a certain direction. › Use words like: balanced, unbalanced, force, motion and acceleration

Notes � Volunteer to share � Now you are going to start filling out the rest of the paper from ebackpack � Copy what is in yellow and include a quick picture

Motion � A change in the position of an object � Caused by force (a push or pull)

Force A push or pull on an object � Measured in units called newtons (N) � Measured with a spring scale � Forces act in pairs � Types of Force: (pick two) › › › gravity electric magnetic friction centripetal

Balanced Forces � When all the forces acting on an object are equal (net force is zero) � Balanced forces do not cause a change in motion. � Balanced forces can change the physical properties of an object without changing its motion. � In your notes, describe an example of a balanced force.

How Can Balanced Forces Affect Objects? � Cause the shape of an object to change without changing its motion � Cause an object at rest to stay at rest or an object in motion to stay in motion (inertia) � Cause an object moving at a constant speed to continue at a constant speed � In your notes, describe an example of a balanced force affecting an object.

Inertia 1. An object at rest will remain at rest until acted upon by an unbalanced force. 2. An object in motion will remain in motion until acted upon by an unbalanced force. 3. When all forces acting on an object are equal (balanced)

Unbalanced Forces � When all the forces acting on an object are not equal � The forces can be in the same direction or in opposite directions. � Unbalanced forces cause a change in motion. � In your notes, describe an example of an unbalanced force.

How Can Unbalanced Forces Affect Objects? � Acceleration is caused by unbalanced forces: › › › � slow down speed up stop start change direction change shape In your notes, describe an example of an unbalanced force affecting an object.

Net Force � The total of all forces acting on an object: › Forces in the same direction are added. Balanced forces do not a change of the �The object will move incause the direction force. in motion. › Forces in opposite directions are subtracted. �An object will move in the direction of the greater force.

Warm Up

� Open your notes from yesterday and prepare to finish taking notes � Copy what is in YELLOW and include a quick picture

Calculating Net Force 1 10 N 30 N http: //commons. wikimedia. org/wiki/File: Jack-in-the-box. jpg A child was playing with a jack in the box. The lid pushed down with 10 N of force, while the spring pushed up with 30 N of force. What is the net force applied by the spring? In your notes, calculate the net force and show all of your work.

Check Your Answer 10 N 30 N http: //commons. wikimedia. org/wiki/File: Jack-in-the-box. jpg A child was playing with a jack in the box. The lid pushed down with 10 N of force, while the spring pushed up with 30 N of force. What is the net force applied by the spring? 30 N to the right + 10 N to the right = 40 N to the right

Calculating Net Force 2 30 N Tug of War Game 50 N Two competitors are playing tug of war. What is the net force? Which direction will the rope move? In your note, calculate the net force and show all of your work.

Check Your Answer 30 N Tug of War Game 50 N Two competitors are playing tug of war. What is the net force? Which direction will the rope move? 50 N to the right – 30 N to the left = 20 N to the right

Force Arrows � Open the Data Sheet in ebackpack � You are completing the first half of the first page � You have 5 minutes to rotate around the room and find three DIFFERENT partners. You will combine arrows. You decide which direction you want them to turn. Fill in the chart

Mass and Weight � Mass is the amount of stuff (matter) in an object. › The mass of an object will remain the same anywhere in the universe. › Mass is measured in grams or kilograms.

Mass and Weight � Weight is the mass (kg) of an object multiplied by the acceleration of gravity (9. 8 m/s 2). › The weight of an object depends on the gravitational pull of the location in the universe. › The gravitational pull on the Moon is only 1/6 of Earth’s gravitational pull. › Weight is measured in newtons (N).

Mass and Weight Example: F=ma A person with a mass of 25 kg x 9. 8 m/s 2 gravitational acceleration is equal to 245 N of weight force. F= 25 kg x 9. 8 m/s 2 F = 245 N The person exerts 245 N of force on the ground. If the person went to the Moon, they would only weigh 1/6 of 245 N.

Force (N) = mass (kg) x acceleration (m/s 2) F ÷ m x a

Force Acceleration (m/s 2) = force (N) ÷ mass (kg) F ÷ m x a

Force Mass (kg) = force (N) ÷ acceleration (m/s 2) F ÷ m x a

Practice The acceleration of a sprinter is 10 m/s 2. The force exerted on the starting blocks is 650 N. What is the mass of the sprinter? Force = Mass = Acceleration =

Check Your Answer The acceleration of a sprinter is 10 m/s 2. The force exerted on the starting blocks is 650 N. What is the mass of the sprinter? Force = 650 N Mass = 65 kg Acceleration = 10 m/s 2 Mass = force ÷ acceleration Mass = 650 ÷ 10 Mass = 65

Practice A 56 kg cart is accelerating at 15 m/s 2. Calculate the force exerted on the cart? Force = Mass = Acceleration =

Check Your Answer A 56 kg cart is accelerating at 15 m/s 2. Calculate the force exerted on the cart? Force = 840 N Mass = 56 kg Acceleration = 15 m/s 2 Force (N) = mass (kg) x acceleration (m/s 2) Force = 56 x 15 Force = 840

Practice A boat is pulling a 54 kg wake boarder. She accelerates at 2 m/s 2. Calculate the force that is causing the acceleration. Force = Mass = Acceleration =

Check Your Answer A boat is pulling a 54 kg wake boarder. The force the boat is exerting on her is 108 N. Calculate her acceleration. Force = 108 N Mass = 54 kg Acceleration = 2 m/s 2 Acceleration = force ÷ mass Acceleration = 108 ÷ 54 Acceleration = 2

Force Mass and Acceleration Cards � Open the Data Sheet again � You are completing the second half of the first page � You have 5 minutes to rotate around the room and find three DIFFERENT groups of three. › Each group must have a Force, Mass, and Acceleration card

Force Mass and Acceleration Cards � The remaining two pages are homework due tomorrow. � You may spend the rest of the period working on them

Warm Up A boat is pulling a 54 kg wake boarder. She accelerates at 2 m/s 2. Calculate the force that is causing the acceleration. Force = Mass = Acceleration =

Review F ÷ m x a

Review � The total of all forces acting on an object: › Forces in the same direction are added. �The object will move in the direction of the force. › Forces in opposite directions are subtracted. �An object will move in the direction of the greater force.

Review � Unbalanced forces cause a change in motion. � Balanced forces do not cause a change in motion.

Warm Up � What is Force measured in? › Newtons (N) � What is acceleration measured in? › D/T › Such as: �m/s, miles/hour, ect � What is mass measured in? › Weight › Such as: �Lbs, kg, ect

Effects of Unbalanced Forces Lab � Remember Your Lab Safety Rules � You must show an understanding of speed, velocity, and acceleration. � This is a Test Grade! � Call me over when you get to the graphing part

Warm Up � Turn in your Effects of Unbalanced Forces Experiment right now even if you are not finished � Write test on your warm up log � Turn in your warm up log � Study your notes and labs for the next ten minutes