Forces

what is a scalar
scalars only have magnituge - e.g. tempreture, distance, speed, time, mass
1 of 46
what is a vector
vectors have magnitude and direction- e.g. displacment, velocity, acceleration, momentum
2 of 46
what is a non-contact force
when the objects are physically separated - e.g. magnetic, gravitational
3 of 46
what is a contact force
when the objects are physically touching - e.g. friction, air resistance
4 of 46
what is a resultant force
when 2 or more forces are acting on an object, the motion of the objects depends on a the combination of all these forces. the combination of the forces is called the resultant, it can be thought to be a single force that could replace a forcesactin
5 of 46
what is mass
mass is the amount of matter in an object
6 of 46
what is weight
weight is the force acting on an object due to gravity, the force of gravity depends on the gravitational field around the earth
7 of 46
what us the equation for weight
weight = mass x gravitational field strength
8 of 46
what is workdone
this is when a force move an object and when energy is transferred and work is done
9 of 46
what is the equation for work done
work done = force x distance moved in the direction of the force
10 of 46
what does hooks law state
it states that the extension of the a spring is directly proportional to the load, provided the limit of proportionality has been exceeded
11 of 46
what is the equation for force
force = spring constant x extension
12 of 46
what is the equation for elastic potential
elastic potential energy = 0.5 x spring constant x extension2 (1/2ke2)
13 of 46
what happens if an object has defrmed elastically
it means the amoun of work done on it is equal to the amount of elastic potential energy which has been stored in it
14 of 46
what is the equation fore moment of force
moment of force = force x distance (M=Fd)
15 of 46
what happens if an object is balanced
anticlockwise moments = clockwise moments (f1 d1 = f2 d2)
16 of 46
what is the equation for pressure
pressure = force/area
17 of 46
what is the equation for pressure in a fluid
pressure = height of the column x density of the liquid x gravitational field strength (p=hpg)
18 of 46
what is the equation for speed
speed = distance/ time
19 of 46
what is the equation for average speed for a journey
average speed = total distance/ total time
20 of 46
what is the equation for acceleration
acceleration = change in velocity/ time
21 of 46
what is the equation for resultant force
resultant force = mass x acceleration
22 of 46
what is newtons first law
if the resultant force acting on an object is zero, then its accelaration will be zero
23 of 46
what is the equation for stopping distance
stopping distance = thinking distance + braking distance
24 of 46
what is the equation for momentum
momentum = mass x velocity (p= mv)
25 of 46
what does force equal
force = rate of change of momentum
26 of 46
how do we make thigns turn from the pivot
if we exert a force further away from the pivot the moment exerted increases
27 of 46
what is the priciple of moments
when the object is at an equlibrium the sum of the anti-clockwise momets about the pivot is equal to the sum of the colckwise moments
28 of 46
what do levers allow
they allow the rotational effects of a force to be transmitted from one object to another
29 of 46
what do gears allow
they allow the rotaional effect of a force to be increased or decreased
30 of 46
eqaution for using gears to increase the rotational effect
input: m1 = f x r output: m2 = f x 2r - increasiong the radius of the gear doubles the moment or the turning force
31 of 46
why does atmospheric pressure decrease with height
air pressure is caused by the force exerted when moving ari particles collide with a surface,
32 of 46
why does atmospheric pressure decrease with height
as the height icreases, the density of the air decrases, which means that air particles collide into objects and other air particles less frequently
33 of 46
equation for distance
s = vt (distance = average speed x time )
34 of 46
how is the speed calculated from a distance time graph
the speed of an object can be claculated from the gradient of its distance time -graph
35 of 46
how do you measure the speed from an object which is accelarating from a distance time graph
you draw a tangent to the line at that time measure the gradient
36 of 46
accelaration equation (2)
v2 -u2 = 2 as
37 of 46
how do work ou the accelartion of an object froma velocity time graph
it is by the gradient
38 of 46
hwo do you calculate the distane travelled by an object
this is by the area underneath it velocity -time graph
39 of 46
newtons second law
an object will accelarate if there is a resultant force acting on it the accelaration of this object is propertional to the rf and inversley proportional to it mass f = ma
40 of 46
newtons third law
when one object exerts a force on another, the second object will exert an equal an opposite force on the first
41 of 46
inertia
the greater the inertial mass of an object the more difficult it is to change it velocity ( a=f/m)
42 of 46
what fators affect reaction time
tiredness, distractions, alcohol consumption and drugs
43 of 46
what factors affect the braking distance
condition of its brakes and tyres, type os road surface, weather conditions and size of the breaking force
44 of 46
what happens to momentum in a closed system
the total momentum before any event is the same after any event
45 of 46
eqaution for momentum 2
force = mass x change in velocity / change in time
46 of 46

Other cards in this set

Card 2

Front

what is a vector

Back

vectors have magnitude and direction- e.g. displacment, velocity, acceleration, momentum

Card 3

Front

what is a non-contact force

Back

Preview of the front of card 3

Card 4

Front

what is a contact force

Back

Preview of the front of card 4

Card 5

Front

what is a resultant force

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Physics resources:

See all Physics resources »See all Forces resources »