dynamics what you need to know

Question 1

what properties do vectors have

Answer 1

it has both magnitude and direction

Question 2

what properties do scalars have

Answer 2

only magnitude

Question 3

examples of vectors

Answer 3

force
velocity
displacement
acceleration

Question 4

examples of scalars

Answer 4

speed
distance
mass
time
energy

Question 5

how do you calculate scalar quantities

Answer 5

add and subtract simply

Question 6

how do you calculate vector quantities

Answer 6

theyre added differently depending on the direction

same direction- add magnitudes keep direction

opposite direction- subtract and the direction is same as the largest

Question 7

double headed arrow means

Answer 7

the resultant vector

Question 8

for finding the direction for a vector always use what trig equation?

Answer 8

trigonometry - tan

Question 9

definition of acceleration?

Answer 9

it’s a measure of the RATE of change of speed - i.e. how much the velocity changes by each second

Question 10

for a speed time graph a steeper slope means a what acceleration

Answer 10

greater acceleration

Question 11

for a speed time graph a less steep graph means a what acceleration

Answer 11

lesser acceleration

Question 12

balanced forces mean what for motion -

Answer 12

no change in motion
(constant velocity)

eg. when a car is driving the friction forces are pushing back and the engine force is pushing forwards and if they’re equal the velocity is constant

Question 13

unbalanced forces cause?

Answer 13

acceleration

Question 14

the relation ship for acceleration is Fu= m a what does everything stand for

Answer 14

Fu= unbalanced force
m=Mass
a= acceleration

Question 15

newtons law of motion

Answer 15

if object A applies a force to object B
Object B applies an EQUAL and OPPISITE force to object A

this situation is often described as Newtons PAIRS this is NOT the same as balanced forces

Question 16

gravity units

Answer 16

Nkg-1

Question 17

any object in free fall on earth will initially accelerate at ? as the unbalanced force acting will only be weight

Answer 17

9.8ms-2

Question 18

when something is in free fall and the forces are BALANCED the object falls at a constant?

Answer 18

terminal velocity

Question 19

active types of energy (where something is happening) examples

Answer 19

kinetic- energy carried by moving objects

sound- energy carried by sound waves

Question 20

types of stored (potential) energy (where noting appears to happen)

Answer 20

gravitational potential- stored in objects raised to a height

nuclear- stored in the nuclei of atoms

Question 21

Work done (Ew) is a measure of?

Answer 21

it’s a measure of the energy transferred when a FORCE acts over a distance

Question 22

gravitational potential energy (Ep) is a measure of?
(definition)

Answer 22

the energy stored in mass, m, RAISED to a height in a GRAVITATIONAL field

Question 23

definition of kinetic energy

Answer 23

a measure of the energy transferred carried by an object with mass travelling at speed

Question 24

all types of energy are interchangeable via transfers- eg.

Answer 24

when an object falls, it loses Ep and gains Ek- speeding up

when a vehicle brakes the Ek is transferred to heat by the work done, Ew, by friction acting over the braking distance

Question 25

what is a projectile

Answer 25

any object in motion under the influence of gravity

Question 26

projectiles have two components to their velocity-

Answer 26

horizontal- Vh- remains constant (there is no acceleration!) vertical- Vv- accelerates due to gravity

Question 27

for projectiles there are also two components to the displacement

Answer 27

Horizontal- Sh=Vh (time on the graph) vertical- Sv= area under graph of Vv and time

Question 28

for projectiles Vertical velocity - Vv is equal to?

Answer 28

gt

Question 29

for projectiles Sv = ?

Answer 29

area under graph