forces and motion
DESCRIPTION
Forces and Motion. Demonstrate and calculate how unbalanced forces change the speed or direction of an objects motion. Force. Any push or pull on an object Act in pairs Measured in Newtons (N) Every force has a magnitude and direction Forces can work together or against each other - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/1.jpg)
Forces and Motion
Demonstrate and calculate how unbalanced forces change the
speed or direction of an objects motion
![Page 2: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/2.jpg)
Force
• Any push or pull on an object• Act in pairs• Measured in Newtons (N)
• Every force has a magnitude and direction• Forces can work together or against each
other• Forces can be balanced or unbalanced
![Page 3: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/3.jpg)
Balanced Forces
• Occurs when there is NO CHANGE in an objects motion
• No acceleration – no change in motion
– objects are at rest or traveling at a constant speed and direction.
![Page 4: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/4.jpg)
Balanced forces
![Page 5: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/5.jpg)
Unbalanced Forces
• Always cause a change in motion - Acceleration
• Acceleration – change in speed or direction of an object
• Starting• Stopping• Speeding up• Slowing down• Turning
![Page 6: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/6.jpg)
Net Force
• Combination of all forces acting on an object.
• Add forces working in the same direction.
• Subtract forces that are working in opposite directions.
![Page 7: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/7.jpg)
Vectors
• Lines with arrows that show force.• Length of the line shows the amount
of force (magnitude)• The arrow shows the direction of the
force.
![Page 8: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/8.jpg)
Add forces acting in the same direction
• 8 N + 6 N = 14 Newtons
![Page 9: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/9.jpg)
Subtract forces acting in opposite directions
• 20 N – 18 N = 2 Newtons
![Page 10: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/10.jpg)
Net Force = 0Forces are balanced
• 20 N – 20 N = 0 Newtons • Forces are balanced - No change in motion
![Page 11: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/11.jpg)
Net force and direction
• What is the net force?
• What direction are they moving?
• Why?
![Page 12: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/12.jpg)
Newton’s 1st Law of Motion
• Law of Inertia
• An object at rest will stay at rest unless acted on by an unbalanced force.
• An object in motion will stay in motion at the same speed and direction unless acted on by an unbalanced force.
![Page 13: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/13.jpg)
In other words…
• An object will keep doing what it is doing unless forces become unbalanced
• Also known as the “Law of Inertia”
• Inertia – An object’s tendency to resist change
![Page 14: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/14.jpg)
Law of Inertia (1st law)
![Page 15: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/15.jpg)
Vehicle Restraints
• What is the purpose of vehicle restraints such as seat belts?
• Describe how Newton’s 1st Law of motion applies to vehicle restraints.
![Page 16: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/16.jpg)
Newton’s 2nd Law of Motion
• Law of Acceleration
• The acceleration of an object by a force in inversely proportional to the mass of the object and directly proportional to the force applied.
![Page 17: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/17.jpg)
In other words…
• The smaller the object, the greater the acceleration AND the larger the object, the smaller the acceleration.
• The smaller the force applied, the smaller the acceleration AND the larger the force applied the larger the acceleration.
![Page 18: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/18.jpg)
Therefore
• Force = Mass X Acceleration• Force = 1,000 kg X .05 m/s/s• Force = 50 Newtons
![Page 19: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/19.jpg)
Acceleration
• The rate of change in the velocity, speed and/or direction, of an object.
• Acceleration = Force/Mass
• Measured in meters/sec2
![Page 20: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/20.jpg)
Force = Mass X Acceleration
• If the amount of force stays the same and the mass of the object increases, what will happen to the amount of acceleration?
• If the amount of force stays the same and the mass of the object decreases what will happen to the amount of acceleration?
![Page 21: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/21.jpg)
What if the acceleration has to stay the same?
• What will have to happen to the amount of force needed if the mass of an object increases?
• What will happen to the amount of force needed if the mass of an object decreases?
![Page 22: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/22.jpg)
Spring Scales
• Used to measure force.
• Use the spring scale to measure the amount of force needed to pull the CPO car up the ramp with different amounts of weight/mass.
• What happens to the amount of force when the mass increases?
![Page 23: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/23.jpg)
Newton’s 3rd Law of Motion
• For every action, there is an equal but opposite reaction
![Page 24: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/24.jpg)
In other words…
• All forces act in pairs.
• When one object exerts a force on a second object, the second object exerts a force back that is equal in size but opposite in direction
![Page 25: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/25.jpg)
Newton’s 3rd Law
![Page 26: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/26.jpg)
Space Shuttle Launch
![Page 27: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/27.jpg)
Speed/Velocity
• How fast an object is moving• Rate at which an object covers a
distance• Speed = distance/time
(meters/second)
![Page 28: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/28.jpg)
Calculating Speed
• While on vacation, Lisa Carr traveled a total distance of 440 miles. Her trip took her 8 hours. What was her average speed?
• Speed = 440 miles/8 hours
• Average speed = 55 miles/hour
![Page 29: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/29.jpg)
Calculating Distance and Time
• Calculating the amount of time it takes to travel a distance.
•Time = distance/speed
• Calculating the distance traveled in a certain amount of time.
•Distance = speed X time
![Page 30: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/30.jpg)
What’s the difference between Speed and
Velocity• Velocity - The rate at which an object
changes position. It’s the measurement of the rate and direction of motion.
![Page 31: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/31.jpg)
Force = Mass x Acceleration
(F = MA)Which object would have the greatest
force?
– A 500 g object accelerating at 10m/s2
or– A 10 g object accelerating at 10m/s2
– Use your formula chart to calculate Force• Force = Mass x acceleration
![Page 32: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/32.jpg)
Force = Mass x Acceleration
• 500g X 10 m/s2 = 5000 Newtons force
• 10g X 10 m/s2 = 100 Newtons of force
• The 500g object exerts a greater force
![Page 33: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/33.jpg)
What is the motion of the object in the graph below?
![Page 34: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/34.jpg)
• No motion • Moving away fast at a constant speed• Stopped (no motion)• Moving away more slowly at a constant speed• Stopped (no motion)
![Page 35: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/35.jpg)
What is the motion of the object in the graph below?
![Page 36: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/36.jpg)
• Moving away at a constant speed• Stopped moving (no motion)• Accelerating
![Page 37: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/37.jpg)
Distance Time Graphs
![Page 38: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/38.jpg)
What is the motion of the object in the graph below?
What is the speed of the object?
![Page 39: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/39.jpg)
Speed = distance ÷ time
• 5 meters in 1 sec.• 25 meters in 5 sec.• 50 meters in 10 sec.
• 5 ÷ 1 = 5 m/s• 25 ÷ 5 = 5 m/s• 50 ÷ 10 = 5 m/s
This object is travelling at a constant speed of 5 m/s (meters per second)
![Page 40: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/40.jpg)
Interpret the graph below
![Page 41: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/41.jpg)
Kinetic vs Potential Energy
• Kinetic Energy – Energy of motion– The faster you are travelling the more
kinetic energy you have
• Potential Energy – Stored energy– The more stored energy you have built
up the more potential energy you have
![Page 42: Forces and Motion](https://reader030.vdocuments.us/reader030/viewer/2022032313/56812c76550346895d91170c/html5/thumbnails/42.jpg)
Where does the rollercoaster have the greatest kinetic
energy vs. potential energy