FM1 - The three laws of motion Flashcards Preview

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Flashcards in FM1 - The three laws of motion Deck (18):

Around what time did Isaac Newton work out the three laws of motion?

Around the time of the Great Plague in the 1660s


What is the first law?

Balanced forces mean no change in velocity


If a train/car is moving at a constant velocity...

The forces must be balanced


What must there be to keep a train going at a steady pace?

Zero resultant force


What is the second law of motion?

If there is an unbalanced force, then the object will accelerate in that direction


What will an unbalanced force (resultant force) always produce?



What are the five forms acceleration can take?

- Starting
- Stopping
- Speeding up
- Slowing down
- Changing direction


The bigger the force...

The greater the acceleration or deceleration


The bigger the mass...

The smaller the acceleration


To get a big mass to accelerate as fast as a small mass...

You need a bigger force


What is an unbalanced force often called?

The resultant force - produces acceleration


What is the equation linking force, mass and acceleration?

F = m x a


What is the third law of motion?

If object A exerts a force on object B then object B exerts the exact opposite force on object A


Use the third law of motion to explain skater A (mass 55kg) and B (mass 65kg) pushing against each other

When skater A pushes on B, she feels and equal and opposite force from skater B. Both skaters feel the same sized force in opposite directions and accelerate away from each other. However skater A will be accelerate more than B as she has smaller mass
(f = ma)


How is the third law of motion applied in swimming?

You push back against the water with your arms and legs, and the water pushes you forwards with an equal-sized force in the opposite direction


How can you investigate motion?

Using a toy car on a ramp


Explain the method for the investigation for motion?

1) Using two light gates and a ramp, mark a start point in the ramp - same point each time
2) Measure the distance between the two light gates
3) Let the car go from top of ramp
4) The light gates are connected to a computer. When the car passes a beam of light is broken and a time is recored
5) Repeat experiment for average time
6) Use these times and the distances recored to find the average speed


What can you change in the experiment to investigate other factors affecting the cars motion (average speed)?

1) Mass - load objects onto cat
2) Friction - use different materials for the ramp
3) Acceleration - changing starting point on the ramp (higher/lower)
4) Speed - change the angle of the ramp
5) Size and shape - use different cars