Mechanics Flashcards

1
Q

Scalars?

A

Qualities with Magnitude

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Vectors?

A

Qualities with Magnitude and direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Speed

A

rate of change of distance v = d/t (ms-1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Velocity

A

rate of change of displacement v = displacement/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Instantaneous speed

A

rate of change of distance at one particular tim\

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Average speed

A

the speed over a period of time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Acceleration

A

rate of change of velocity a = ∆v/t (ms-2)
- Whether acceleration is +ve or -ve depends on the direction
- not if its speeding up or down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

v = u + at

A

v = final velocity (ms-1)
u = initial velocity (ms-1)
a = acceleration (ms-2)
t = time (s)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

v^2 = u^2 + 2as

A

v = final velocity (ms-1)
u = initial velocity (ms-1)
a = acceleration (ms-2)
s = displacement (m)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

s = ut + 1/2at^2

A

t = time (s)
u = initial velocity (ms-1)
a = acceleration (ms-2)
s = displacement (m)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

s = (v+u)t/2

A

t = time (s)
u = initial velocity (ms-1)
v = final velocity (ms-1)
s = displacement (m)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Range

A

How far it travelled horizontally
Range = Horizontal velocity x time of flight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Mass (m)

A

amount of matter in an object (kg) (does not ∆ if an object ∆ its position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Weight (W)

A

force of gravity acting on an object (N) (it will ∆ if an object ∆ its position)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

W = mg

A

W = Weight (N)
m = Mass (kg)
g = gravity (9.81 Nkg-1 on earth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Newton’s first law

A

“an object continues in uniform motion in a straight line or at rest unless a resultant external force acts”

17
Q

Newton’s second law

A

“the resultant force on an object is proportional to the acceleration providing the mass of the object remains constant”
- bigger force -> bigger acceleration
- F = ma

18
Q

Newton’s third law

A

“for every action on one object there is an equal but opposite reaction on another object”

19
Q

F = ma

A

F = Force (N)
m = mass (kg)
a = acceleration (ms-2)

20
Q

Ff ≤ μsR

A

Ff = static friction force (N)
μs = coefficient of static friction (max value = 1)
R = normal reaction force (N)
Static Friction = “about to move”

21
Q

Ff = μdR

A

Ff = dynamic friction force (N)
μd = coefficient of dynamic friction (max value = 1)
R = normal reaction force (N)
Dynamic friction = sliding friction (not affected by speed) μd < μs

22
Q

Ek = 1/2 mv^2

A

Ek = kinetic energy (J)
m = mass (kg)
v = speed (ms-1)

23
Q

∆Ep = mg∆h

A

∆Ep = Gravitational potential energy (J)
m = mass (kg)
g = gravity
∆h = change in height

24
Q

Ep = 1/2 k∆x^2

A

Ep = Elastic potential energy (J)
k = spring constant (Nm-1)
∆x = extension or compression (m) (change in length)
F (applied force (N)) = ∆x

25
W = Fs
W = work (J) F = force (N) s = displacement (m)
26
W = F s cosθ
W = work (J) (transfer of energy) F = force (N) s = displacement (m) θ = angle between F & S
27
Force required to lift an object =?
Objects weight
28
P = Fv
P = power (W)(Js-1) F = force (N) (constant) v = velocity (ms-1) (constant)
29
Efficiency =
useful work out/total work in = useful power out/total power in
30
p = mv
p = linear momentum (kgms-1)(Ns) m = mass (kg) v = velocity (ms-1)
31
Conservation of momentum definition?
"the total linear momentum of a system remains constant provided no resultant external force acts (e.g. friction)". total p-before = total p-after
32
Elastic collision =
no kinetic energy is lost during the collision
33
inelastic collison =
kinetic energy is lost
34
Ek = p^2/2m
Ek = kinetic energy (J) p = momentum (kgms-1)(Ns) m = mass (kg)
35
Impulse =?
Change in momentum (F∆t = ∆p)
36
F = ∆p/∆t
F = Force (N) ∆p = change in momentum (impulse) (kgms-1)(Ns) ∆t = change in time
37
Explosions
Kinetic energy will always increase in an explosion p=mv big m = little v little m = big v
38
projectile?
An object moving through air under the influence of only one force, gravity