forces core questions

Question 1

define speed

Answer 1

how much distance is covered in a given time

Question 2

define acceleration

Answer 2

how much speed increases or decreases in a given time

Question 3

state the equation for calculating speed

Answer 3

speed = distance/time

Question 4

state the units for speed

Answer 4

m/s

Question 5

what does a straight line on a distance-time graph show

Answer 5

object travelling at a steady speed

Question 6

what does a curved line on a distance-time graph show

Answer 6

object speeding up or slowing down

Question 7

what does a horizontal line on a distance-time graph show

Answer 7

object at rest not (not moving)

Question 8

what is the unit for force

Answer 8

newton (n)

Question 9

name the apparatus used to measure forces

Answer 9

newton meter

Question 10

define force

Answer 10

a push or pull that acts on an object due to the interaction with another object

Question 11

define contact force

Answer 11

a force that acts when objects are physically touching

Question 12

define non-contact force

Answer 12

a force that acts when objects are physically separated

Question 13

name five examples of contact forces

Answer 13

friction
air resistance
tension
compression
normal contact force

Question 14

name three examples of non-contact force

Answer 14

gravitational force
electrostatic force
magnetic force

Question 15

define resultant force

Answer 15

single force that can replace all the forces acting on an object and have the same effect

Question 16

name two things that can happen when the forces on an object are balanced

Answer 16

object remains at rest
object remains at constant speed and direction

Question 17

name four things that could happen when the forces on an object are unbalanced

Answer 17

object speeds up
object slows down
object changes shape
object changes direction

Question 18

what would the resultant force on an object be if the forces are balanced

Answer 18

zero

Question 19

what is the name of the diagram used to represent the forces acting on an object

Answer 19

free-body diagram

Question 20

define friction

Answer 20

force opposing motion which is caused by the interaction of surfaces moving over each other

Question 21

define drag

Answer 21

friction force when one object is a liquid or gas

Question 22

define tension

Answer 22

force extending or pulling apart

Question 23

define compression

Answer 23

force squashing or pushing together

Question 24

define normal contact force

Answer 24

push force acting between two solid objects

Question 25

define air resistance

Answer 25

friction force acting between an object and air particles

Question 26

state two examples of situations where it is useful to reduce friction

Answer 26

sports vehicles

Question 27

state two ways of reducing friction or drag

Answer 27

make objects streamlined use lubricants

Question 28

state newtons third law

Answer 28

when objects interact the forces they exert on each other are equal and opposite

Question 29

state the equation for hookes law

Answer 29

force = spring constant x extension

Question 30

define moment of a force

Answer 30

the turning effect of a force

Question 31

state the equation for moment of a force

Answer 31

moment of a force = force x distance to the pivot

Question 32

state the unit for moment of a force

Answer 32

Nm (newton metre)

Question 33

state what happens when the clockwise and the anticlockwise moments are equal acting on an object

Answer 33

the object balances

Question 34

state the units of spring constant

Answer 34

newton per metre (N/m)

Question 35

what happens when the clockwise and anticlockwise moments acting on an object are unequal

Answer 35

the object rotates

Question 36

what is meant by the mass of an object

Answer 36

mass is a measure of how much matter there is in an object

Question 37

what is the unit for mass

Answer 37

kg

Question 38

what is meant by the weight of an object

Answer 38

weight is a measure of the size of the pull of gravity on the object

Question 39

what is the unit for weight

Answer 39

newton (N)

Question 40

what are the two factors that affect the pressure an object exerts

Answer 40

the force and the area over which the force is exerted

Question 41

what is the equation for calculating pressure

Answer 41

pressure = force/area