1 / 38

P2.1 Force

http://www.youtube.com/watch?v=Zer5IUrZa2Y. P2.1 Force. Overview.

prema
Download Presentation

P2.1 Force

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. http://www.youtube.com/watch?v=Zer5IUrZa2Y P2.1 Force

  2. Overview Forces can cause changes to the shape or motion of an object. Objects can move in a straight line at a constant speed. They can also change their speed and/or direction (accelerate or decelerate). Graphs can help us to describe the movement of an object. These may be distance–time graphs or velocity–time graphs. Candidates should use their skills, knowledge and understanding to: • interpret data from tables and graphs relating to speed, velocity and acceleration • evaluate the effects of alcohol and drugs on stopping distances • evaluate how the shape and power of a vehicle can be altered to increase the vehicle’s top speed • draw and interpret velocity–time graphs for objects that reach terminal velocity, including a consideration of the forces acting on the object

  3. P2.1.1 Force - Objectives • Find out what happens when two objects interact • Investigate the ‘resultant’ force on an object • State what happens when a resultant force acts on an object

  4. This is an object This is the force

  5. This is an object This is the force

  6. Lift Thrust Drag Weight

  7. Lift Drag Thrust Weight

  8. 1 3N 5N 2N 96N 96N 0N 2 3N 8N 5N 3 EXTENSION 4N 5N 4 3N

  9. If the resultant force acting on a stationary object is: Zero The object will remain stationary Not zero The object will accelerate in the direction of the resultant force.

  10. If the resultant force acting on a moving object is: Zero The object will continue to move at the same speed and in the same direction Not zero The object will accelerate in the direction of the resultant force.

  11. Reaction Weight

  12. Reaction Thrust Drag Weight

  13. P2.1.2 Force and Motion - Objectives • State what happens when a resultant force acts on an object • Investigate what affects the acceleration of an object • Use F = m x a in calculations

  14. 3N 8N The object will accelerate in the direction of the resultant force. 5N Resultant Force = Resultant Force = Mass x Acceleration [N] [kg] [m/s2]

  15. Q1. The vehicle has a mass of 1200kg. The engine is applying a forward force of 500N and the friction from the road is a force of 70N. a) What is the acceleration of the vehicle? (show your working) Total forward force = 500 – 70 = 430N Mass = 1200kg F = ma a = F/m = 430/1200 = 0.36 m/s²

  16. P2.1.2 Force and Motion - Objectives • Read a velocity-time graph • Use a graph to perform calculations • Recognise the difference between speed and velocity • Calculate the acceleration of an object

  17. P2.1.2 Force and Motion • Finish your table, calculating the speed (velocity) of the paper. • Plot a graph on A4 graph paper: • Velocity (in m/s) on vertical (y) axis • Time (in s) on horizontal (x) axis • What does this graph show? This is not an easy task – do not be afraid of getting it wrong

  18. Velocity-time graph • A mountain biker accelerates uniformly down a ramp taking 10s to reach 20m/s. • They stay at 20m/s for the next 30s of the course. • They then take 5s to slow down to 10m/s as they enter the technical, steep part of the track. They stay at 10m/s for the next 20 seconds. • Breaking out of the woods they accelerate to 30m/s in 5s as they hit the high speed part of the course. They maintain 30m/s for the next 20s. • They cross the finish line and it takes them 5s to come to a stop. http://www.youtube.com/watch?v=LSqj8c8LaBQ&feature=related

  19. All these tasks need to be completed at some point Complete ‘Speed and acceleration 2’ worksheet Answer all Summary Questions in Textbook: Pages 109, 111 and 113 Past exam questions: 1, 2 and 3 on page 117 Sort out your book • Stick in sheets • Complete unfinished work

  20. Thinking Distance + Braking Distance Stopping Distance = • Drinking • Drugs • Tiredness • Distractions • Icy road • Wet road • Poor brakes • Worn tyres

  21. Thinking Distance + Braking Distance Stopping Distance = Speed

  22. Thinking Distance + Braking Distance Stopping Distance = Speed

  23. P2.1.3 Forces and Braking When the brakes of a vehicle are applied, work done by the friction force between the brakes and the wheel reduces the kinetic energy of the vehicle and the temperature of the brakes increase. Kinetic Energy Heat Energy

  24. P2.1.4 Forces and Terminal Velocity http://www.youtube.com/watch?v=HN-U_INtUSs&feature=related http://www.youtube.com/watch?v=CYTYia9k4Tw

  25. Weight P2.1.4 Forces and Terminal Velocity 1 F = mg When a parachutist first jumps out of the plane

  26. Weight P2.1.4 Forces and Terminal Velocity Drag 2 F = 0 When they reach terminal velocity

  27. Weight P2.1.4 Forces and Terminal Velocity Drag 3 F = up When they open their parachute

  28. Weight P2.1.4 Forces and Terminal Velocity Drag 4 F = 0 When they descend at a lower terminal velocity

  29. Weight P2.1.4 Forces and Terminal Velocity Reaction 5 F = up When they land on the ground

  30. v-t graph for terminal velocity 2 Velocity / m/s 3 1 4 5 Time / seconds

  31. P2.1.5 Force and Elasticity - Objectives • Realise what happens when a force acts on an object • Reason why objects stretch and store energy • Relate stored energy to the work done • Investigate how the extension is related to the force applied

  32. Results table

  33. Force-extension graph Spring Extension / m Elastic Band Force / N

More Related