Mass And Weight

Question 1

what does the gradient of a distance-time graph represent

Answer 1

the speed of an object

Question 2

what is velocity

Answer 2

its speed in a particular direction

Question 3

what does the slope on a distance time graph represent?

Answer 3

the acceleration of an object

Question 4

how to find acceleration on the graph

Answer 4

velocity / time in s

Question 5

what does the gradient of a velocity-time graph represent?

Answer 5

the acceleration

Question 6

what does the area under a velocity time graph represent

Answer 6

the distance covered

Question 7

what is mass

Answer 7

how much stuff there is in a object

Question 8

what is weight

Answer 8

how much including gravity the mass weighs.

Question 9

how is weight calculated

Answer 9

mass x gravitational field strength

Question 10

how is ‘work done’ calculated

Answer 10

force x distance

Question 11

what is density

Answer 11

mass per unit volume

Question 12

how to calculate density

Answer 12

mass / volume

Question 13

how can you measure density of an irregular shape

Answer 13

water displacement using an eureka can. the volume of the object is equal to the volume of the water that is forced through the spout

Question 14

what is newtons first law of motion

Answer 14

objects with greater mass will resist change in motion more that objects with less mass.

Question 15

how do you calculate resultant forces

Answer 15

mass x acceleration

Question 16

what is hooke’s law?

Answer 16

when an elastic object such as a spring it stretched, the increased length is called it’s extension. the extension of an elastic object is directly proportional to the force applied to it.

Question 17

how to measure force

Answer 17

constant x extension

Question 18

why would the equation not work

Answer 18

when the limit of proportionality is exceeded.

Question 19

what is the extension

Answer 19

the new length minus the unloaded length

Question 20

what is the gradient of the line called

Answer 20

the spring constant, k

Question 21

what does the greater the value of k mean

Answer 21

the stiffer the spring

Question 22

what is newtons second law of motion

Answer 22

the relationship between force mass and acceleration

Question 23

what happens if the mass is the same

Answer 23

more force causes more acceleration

less force causes less acceleration

Question 24

what happens if the force is the same

Answer 24

more mass causes less acceleration

less mass causes more acceleration

Question 25

what happens if the acceleration is the same

Answer 25

more mass needs more force

less mass needs less force

Question 26

how can force be calculated

Answer 26

mass x acceleration

Question 27

what is pressure

Answer 27

pressure is the force per unit area

Question 28

how to calculate pressure

Answer 28

force / area

Question 29

how to increase pressure

Answer 29

increase the force or reduce the area the force acts on

Question 30

how to reduce pressure

Answer 30

decrease the force or increase the area the force acts

Question 31

what is a moment

Answer 31

is the turning effect of a force around a fixed point called a pivot

Question 32

what does the size of a moment depend on

Answer 32

the size of the force applied

the perpendicular distance from the pivot to the line of action of the force

Question 33

why is less force needed to open a door

Answer 33

pushing it furthest from the hinge than at the side closest to the hinge. to push at the hinge side of the door requires force to be exerted because the distance is shorter

Question 34

how to calculate a moment

Answer 34

force x distance

Question 35

how to balance moments

Answer 35

where an object is not turning around a pivot, the total clockwise moment must be exactly balanced by the total-anticlockwise moment. we say that the opposing moments are balanced.

sums of the clockwise moments = sums of anticlockwise moments

Question 36

how do levers rely on moments

Answer 36

they rely on the principle of moments to acts as ‘force multipliers’. they reduce the effort needed to move the load by increasing the distance over which it is acting.

Question 37

what is the centre of mass

Answer 37

centre of mass, where an object will balance on. centre of mass in a symmetrical shape is where the axes of symmetry cross

Question 38

how to find the centre of mass in a regular shape

Answer 38

1. drill a small hole in shape and hang it up so that it can still swing without obstruction
2. hang a plumb line from the same suspension point. this makes a vertical line directly below.
3. drill another hole at a different location within the object.
4. hang another plumb line to determine the vertical and mark it on
5. the point at which the two marked lines cross is the centre of mass