P5:forces and motion Flashcards

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1
Q

whats a contact force

A

when objects physically touch

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2
Q

whats a non contact force

A

when not touching

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3
Q

whats a vector

A

a quantity that has magnitude and direction

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4
Q

whats a scalar

A

quantity that only has magnitude

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5
Q

whats a resultant force

A

overall force acting on a object

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6
Q

give examples of scalars

A

distance, speed , mass, energy, temperature

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7
Q

give examples of vectors

A

displacement, velocity, acceleration, force, momentum

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8
Q

how is thinking distance affected

A

speed, distraction, alcohol, drugs and tiredness

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9
Q

how is breaking distance affected

A

speed, condition of breaks, tires and roads, weather condition

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10
Q

what does momentum(kgm/s) =

A

mass(kg) x velocity(m/s)

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11
Q

what are all the EM emitted by

A

electrons

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12
Q

how are EM waves produced

A

when electrons lose energy

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13
Q

What does a higher frequency mean

A

more energy which means shorter wave lengths

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14
Q

what does work done =

A

force x distance

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15
Q

what does force = when it comes to elasticity

A

spring constant (n/m) x extension(m)

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16
Q

what does acceleration =

A

change in velocity(m/s)/time

17
Q

what is suvat

A

s : displacement(m/s)
u : initial velocity
v : final velocity
a : acceleration(m/s^2)
t : time

18
Q

how do you calculate weight(n)

A

mass(kg) x gravitational field strength(n/kg)

19
Q

whats newtons first law of motion

A

when theres no resultantant force an objects motion is constant

20
Q

whats newtons 2nd law of motion

A

force(n) = mass(kg) x acceleration(m/s^2)

21
Q

what is the practical for acceleration

A

accelerate trolley with mass on string
use photogates to measure acceleration
change weight on string
draw a force - acceleration graph
straight line across origin which shows that f and a are directly proportional

22
Q

whats newtons 3rd law of motion

A

for every action there is an equal an opposite force

23
Q

in a closed system what happens to momentum before an event and after an event

A

total momentum before and event is equal to the total momentum after and event

24
Q

what happens in collisions

A

Momentum is conserved so the momentum of object increases
Which decreases the momentum of the other object
Mass of object is constant so velocity decreases

25
Q

Reasons why speed may change

A

Surface
Tiredness
Force

26
Q

What happens when a force moves through a fluid

A

Force drags on it
It acts in the opposite direction of the object
The greater the speed the greater the drag

27
Q

What happens to an object falling through a fluid

A

At the start weight is equal to resultant force
Resultant force causes them to fall
Air resistance is an upwards force that acts opposite to weight
Air resistance is low at the start
Resultant force decreases because of air resistance
Air resistance increases as they collide with more particles
Weight is constant so resultant force decreases and they are accelerating more
Air resistance will increase to the same amount as the weight
No resultant force
So no resultant force
Reach terminal velocity

28
Q

How does surface area affect air resistance

A

The larger the area which collisions can take place
More air resistance
Resultant force changes direction
Slow down
Resultant force decreases
Until terminal velocity