motion and forces

Question 1

Distinguish between a scalar and vector quantity and provide three examples for each

Answer 1

scalar quantities specify size or magnitude but NOT direction e.g. distance and speed
vector quantities specify direction as well as magnitude e.g. displacement and velocity

Question 2

define the term distance and state its standard unit

Answer 2

distance is the total path length of motion of travel
measure in m,km,cm

Question 3

define the term displacement and state its standard unit

Answer 3

displacement is the absolute change in position. straight line distance from where you started to where you finished
measure in cm,m,km to the north, south, east, west

Question 4

solve mathematically based problems relating to distance travelled and displacement of an object

Answer 4

distance equals all sectors added up
displacement equals pythag for km then trig for degrees use -1

Question 5

define speed and state its standard unit

Answer 5

speed is the measure of the rate at which an object moves over a distance
measures in km/hr

Question 6

state and label the equation used to calculate speed

Answer 6

speed = distance/time taken

Question 7

solve mathematically based problems relating to average speed

Question 8

convert between the unit km/hr and m/s

Answer 8

km/hr-m/s is km x 1000 over 60 x 60
m/s - km/hr is m/1000 over 1/60/60/

Question 9

define velocity and state its standard unit

Answer 9

the rate at which an objects position is changing measured in km/hr north, east, south, west

Question 10

state and label the equation used to calculate average velocity

Answer 10

displacement/time taken

Question 11

solve mathematically based problems relating to speed

Question 12

define acceleration and state its standard unit

Answer 12

the rate at which an objects velocity changes, or the change in velocity per unit time.
measured in m/s/s

Question 13

state and label the equation used to calculate average acceleration

Answer 13

change in velocity/time taken for change
v-u/t
v = final velocity
u = initial velocity
t = time taken

Question 14

solve mathematically based problems relating to average acceleration

Question 15

determine the speed of an object from a ticker-timer tape

Answer 15

interval length/time

Question 16

determine the acceleration of an object from a ticker timer tape

Answer 16

change in velocity/time
change in velocity = final velocity (last interval speed) - initial velocity (first interval speed)
time = number of intervals x 0.02

Question 17

describe the ticker timer tape produced by an object moving with
1 - a constant speed
2 - a positive acceleration
3 - negative acceleration

Answer 17

1 - the dots stay the same amount of space apart
2 - dots get further apart
3 - dots become closer together

Question 18

construct and analyse distance time graphs, including determining the speed of an object by calculating the gradient

Answer 18

straight line sloping upwards = constant speed
horizontal line = stationary zero speed
line curving upwards = accelerating speed
line curving downwards = decelerating speed
gradient = rise/run
rise = distance/y intercept
run = time/x intercept

Question 19

construct and analyse speed time graphs, including determining the acceleration from the gradient and the distance travelled from the area under the curve

Answer 19

straight line sloping upwards = constant acceleration
horizontal line = constant speed no acceleration
line curving upwards = increasing acceleration
line curving downwards = negative acceleration/deceleration
gradient = rise/run
rise = speed/y intercept
run = time/x intercept
under the curve = distance travelled = speed x time

Question 20

define a force and state is standard unit

Answer 20

push, pull or twist
measure in newtons (N)

Question 21

construct and analyse free body diagrams (diagrams in which forces are represented as arrows)

Answer 21

longer the arrow the larger the force
direction of the arrow is the direction of the force
down arrow - force gravity (Fg)
up arrow - force normal (Fn)
forward arrow - Force applied - (Fa)
backwards arrow - Force friction - (Ff)

Question 22

define the term net force

Answer 22

the overall force acting on an object, calculated by summing all the individual forces acting on it, taking their direction into account

Question 23

describe the effect of a non zero net force acting on an object

Answer 23

it will change its direction, shape or acceleration (move faster or slower)

Question 24

state newtons first law of motion

Answer 24

Inertia which means that an object that is not moving will not move until a force acts upon it and an object that is in motion will not change its velocity (including stopping) until a force acts upon it

Question 25

describe an everyday situation where newtons first law of motion is clearly demonstrated

Answer 25

if a car is sitting still relative to the ground it will stay still no matter what table cloth trick where when you pull the table cloth the water will stay in place

Question 26

state newtons second law of motion using words

Answer 26

the relation between force mass and acceleration when a object has more mass it is harder to move (accelerate) so if you push two objects with the same force the lighter one willmove faster

Question 27

state and label the mathematical equation describing newtons second law of motion

Answer 27

F=ma force = mass x acceleration a = F/m m = F/a

Question 28

solve mathematically based problems using newtons second law of motion equation

Question 29

state newtons third law of motion

Answer 29

for every action there is a equal and opposite reaction all forces occur in pairs e.g. when you push against a wall the wall pushes back

Question 30

describe a range of action-reaction force pairs

Answer 30

they are equal in magnitude, opposite in direction, act on different objects. e.g. walking, swimming, bouncing a ball

Question 31

analyse qualitatively everyday situations involving motion in terms of newtons laws

Answer 31

Newton's First Law (inertia) explains why a car keeps moving forward after a crash, while the second law (F=ma) explains why heavier objects require more force to move. The third law (action-reaction) explains how we walk and why a rocket takes off