Any influence that causes an object to undergo a specific change
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What are the units ofr force?
Newtons (N)
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Whenever to objects push or pull on each other...
They exert equal and opposite forces on one another
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What is resultant force?
The sum of the individual forces.
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Why does force have to have a direction?
Because it is a vector
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What is zero resulatant force?
When the resultant force on an object is zero because: it remains stationary or continues to move at the same speed in the same direction
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What is non-zero resulatnt force?
When the resultant force on an object is not zero
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If an object is acted on by two unequal forces in opposite directions, the resultant force is...
Equal to the difference between the two forces, in the direction of the larger force
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What is a balanced force?
Where the forces are of equal size in opposite directions, resultant force is 0, objects are stationary/constant speed
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What is an unbalanced force?
Where the forces are of unequal size in opposite directions, resultant force>0, acceleration
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What types of forces are there?
Push, pull, upthrust, weight, friction, air/water resistance (drag), tension, reaction, lift and force from the engine (thrust)
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Resultant force is proportional to...
Acceleration
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Mass is inversely proportional to...
Acceleration
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How do we calculate force?
Mass (kg) * Acceleration (m/s squared)
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How do we calculate mass?
Force/acceleration
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How do we calculate acceleration?
Force/mass
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What is mass?
The amount of matter (particles) in an object
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What is mass measured in?
Kilograms
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What is the gravitational field strength on Earth?
9.8 (10)
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How do we calculate weight (N)?
Mass (kg) * gravitational field strength (m/s squared)
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What is the gravitational field strength o the moon?
1.6
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In a vaccuum, everything will fall at the ............, irrospective of the mass
Same rate
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Describe the process of a parachutist falling through the sky.
Weight makes her accelerate, as she accelerates so will air resistance, weight and air resistance balance out (constant speed/terminal velocity), opens parachute and increases air resistance, decelerates, air resistance and weight balance out again
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Force is proportional to...
Extension
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What is Hooke's Law?
The force applied to a material is directly proportional to the extension as long as it remains within the limit of proportionality
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What is the limit of proportionality?
The point at which the material will not return back to its original state
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How do we calculate Hooke's Law?
Force (N) = Spring constant (N/m) * Extension (m)
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What axis does extension go on?
X axis
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What axis does force go on?
Y axis
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What is the gradient of a force extension graph?
Spring constant
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What does friction do?
Slow things down
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Reaction forces are always...
Equal and opposite
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Drag increases as the .... increases
Speed
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What is terminal velocity?
When the force is equal to the resistance, resultant force is 0, moving at constant speed
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What do objects have to fall through to reach terminal velocity?
Fluids
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What do frictional forces increase with?
Speed
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Explain why the car reaches top speed, even though the thrust force remains constant.
As speed increases so does drag, thrust=drag and they balance out, resultant force=0
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