P4 - Explaining Motion

Question 1

what is a force?

Answer 1

is a push or pull, on an object, that is caused by it interacting with another object

Question 2

why are forces considered vector quantities?

Answer 2

both have direction and magnitude (newtons)

Question 3

what is the normal contact force?

Answer 3

are the “push” forces that two touching objects always exert on each other

Question 4

what is newton’s third law?

Answer 4

when two objects interact, the forces they exert on each other are equal (magnitude) and opposite (direction)

Question 5

what is mass?

Answer 5

it’s the amount of matter in an object
measured in kg

Question 6

what does everything with mass have?

Answer 6

everything that has mass has a gravitational field around it

Question 7

what is weight?

Answer 7

when an object is on a planet a downwards force acts on the object due to gravitational attraction between the object and planet

Question 8

how can you calculate weight?

Answer 8

weight (N) = mass (kg) x gravitational field strength (N/kg)

Question 9

what does gravitational field strength equal on the earth?

Answer 9

g = 10N/kg

Question 10

what are scalar quantities?

Answer 10

are just numbers, they simply tell you the “size” or magnitude of the thing you’re measuring

Question 11

name some examples of scalar quantities?

Answer 11

speed, distance, time, mass

Question 12

what are vector quantities?

Answer 12

tells you both the size and direction

Question 13

what are some examples of vector quantities?

Answer 13

force, velocity, displacement, and acceleration

Question 14

what are vectors usually represented by??????

Answer 14

by an arrow, the length of the arrow shows the magnitude, and the direction of the arrow shows the direction of the quantity

Question 15

what are the 3 ways the motion of the object can be described?

Answer 15

speed, direction, and whether its speed is changing

Question 16

what is speed?

Answer 16

is how fast the object is going, with no regard to direction

Question 17

what is velocity?

Answer 17

is the speed of the object in a given direction

Question 18

what is the speed, distance, time formula?

Answer 18

average speed (m/s) = distance (m) ÷ time (s)

Question 19

what is acceleration?

Answer 19

is the change of velocity of an object in a certain amount of time

Question 20

if an object accelerates, is must be?

Answer 20

speeding up or changing direction

Question 21

how can you find the average acceleration?

Answer 21

acceleration (m/s²) = change in speed (m/s) ÷ time taken (s)

Question 22

how do you work out speed from a distance time graph?

Answer 22

the gradient of a specific point of the graph is the speed
use the ∆ distance / ∆ time for the speed

Question 23

how do you work out the speed/gradient of acceleration or decertation on a distance-time graph?

Answer 23

you draw a tangent in line with the curve
you choose 2 points on the tangent and calculate the ∆ in distance and time and divide both changes ∆

Question 24

what does the gradient on a velocity time graph tell us?

Answer 24

acceleration

Question 25

what is the formula for the area of a triangle?

Answer 25

1/2 base x height

Question 26

how can you work out the distance in a velocity time graph?

Answer 26

work out the area of inside the curve

Question 27

what are freebody diagrams?

Answer 27

show all the forces acting on a object

Question 28

what is a resultant force?

Answer 28

if you have a number of forces acting at a single point, you can replace them with a single force that takes in account the sizes and directions of all the forces added together

Question 29

what force does weight of an object create?

Answer 29

gravity??

Question 30

how to use scale drawings to find the resultant force?

Answer 30

draw all the forces acting on a object, to scale, "tip to tale" then draw a straight line from the start force to the end of the last force; the resultant force

Question 31

if all the forces acting on an object combine to give a resultant force of zero, the object is in??

Answer 31

equilibrium

Question 32

what does Newton's first law say?

Answer 32

a resultant force is needed to change the motion of an object

Question 33

what does Newton's first law say about an object travelling in a straight line?

Answer 33

if the resultant force on a moving object is zero, it will just carry on moving at a constant speed in a straight line

Question 34

what does Newton's first law say about stationary objects?

Answer 34

if the resultant force on a stationary object is zero, the object will remain stationary

Question 35

what are the 3 things that could happen when a non-resultant force acts on an object?

Answer 35

- object will accelerate if the force is in the same direction as the object's motion - the object will slow down if the force in in the opposite direction to the object's motion

Question 36

what is Newton's second law?

Answer 36

non-zero resultant force acts on an object, then it will cause the object to accelerate

Question 37

what is F = m x a

Answer 37

force (N) = mass (kg) x acceleration (m/s²)

Question 38

what is inertia?

Answer 38

the tendency for the motion of an object to remain unchanged