Forces Flashcards
(20 cards)
Non-contact forces
Gravity - mass, magnetic, electrostatic - charge
Newton’s first law
Every object remains at rest or at a constant velocity unless acted on by a resultant force
Field
Area around an object where a force can act
Newton’s third law
If object A exerts a force on object B, object B will exert a force on object A that is the same and acting in the opposite direction e.g. you pushing on the wall and the wall pushing on you (act on different objects)
For every action force, there is an equal reaction force acting in the opposite direction
Newton 3rd law pairs
Act on different objects
Equilibrium force pairs
Act on 1 object
Oxygen atom
1.2 x 10^-10 m
How can weight be measured
Newton meter
Newton’s second law
If the resultant force acting on a body is not zero, it will accelerate in the direction of the resultant force. Acceleration is directly proportional to resultant force and inversely proportional to the mass.
Walking speed
1.4m/s or 3.1mph
Cycling speed
6m/s or 13mph
Airplane speed
230m/s or 515mph
Speed of sound
343m/s or 767mph
Force def
Something that acts on an object and can change its shape, direction or speed
Reaction time
The time between a person detecting a stimulus and their response
How to measure reaction times
Computers, electric circuits, ruler drop test
Braking distance
The distance travelled after the brake pedal is pressed until the car hits
Thinking distance
The distance travelled while a driver reacts to press the brake pedal
Affects braking
Friction of tyres, road surface, weather, brake quality, mass, kinetic energy
Affects thinking
Drugs (alcohol, caffeine), tiredness, distractions
