Forces pt1 (Scalar, contact, Gravity, Work done, Elasticity, moment)

Question 1

What is a force?

Answer 1

A force is a push or pull that acts on an object due to the interaction with another object.

Question 2

what is a scalar quantity?

Answer 2

magnitude only

Question 3

what is a vector quantity?

Answer 3

magnitude and direction

Question 4

What is are contact forces?

Answer 4

when the objects are physically touching

Question 5

What is a non-contact forces?

Answer 5

when the objects are physically separated.

Question 6

examples of non-contact forces (3)

Answer 6

gravitational force electrostatic force magnetic force

Question 7

What type of quantity is force?

Answer 7

vector

Question 8

Examples of contact forces?

Answer 8

friction, air resistance, tension and normal contact force.

Question 9

what is gravity?

Answer 9

a force of attraction between all masses

Question 10

What is the gravitational force close to Earth caused by?

Answer 10

the gravitational field around theEarth.

Question 11

what is mass?

Answer 11

the amount of matter an object contains - this is constant

Question 12

what is the weight?

Answer 12

the force acting on an object due to gravity

Question 13

what is the equation for gravitational field strength, mass and weight?

Answer 13

weight = mass x gravitational field strength

Question 14

What is the connection between weight and mass

(proportion)

Answer 14

they are directly proportional

Question 15

what is work done?

Answer 15

when a force causes an object to move

Question 16

what are the two units for work done

Answer 16

joule and newton metres

Question 17

what is the equation for force, work done and distance?

Answer 17

work done = force x distance

Question 18

what happens when work is done?

Answer 18

energy transfers take place within the system

Question 19

the extension of an elastic object is ___________ to the force applied , provided that the ___________ is not exceeded

Answer 19

directly proportional

limit of proportionality

Question 20

what must happen to change the shape of an object?

Answer 20

more than one force must be applied

Question 21

what does elastically deformed mean?

Answer 21

when an object returns to its original shape after the forces are removed

Question 22

what does inelastically deformed mean?

Answer 22

when an object does not return to its original shape

Question 23

what happens when the limit of proportionality for the extension of an elastic object and applied force has been exceeded? (3)

Answer 23

• doubling the force will no longer exactly double the extension - the relationship becomes non-linear - a force-extension graph will stop being a straight line

Question 24

what is the equation for , extension , force, and spring constant

Answer 24

force= spring constant x extension

Question 25

what is spring constant?

Answer 25

it indicates how easy it is to stretch or compress a spring- the higher the spring constant, the stiffer the spring.

Question 26

when is the work done on the spring and the elastic potential energy stored not equal

Answer 26

when the spring is inelastically deformed

Question 27

what is the moment of a force?

Answer 27

the turning effect of a force

Question 28

what is the equation for distance, moment and force?

Answer 28

moment = force x distance

Question 29

What is the distance in terms of the moment?

Answer 29

the perpendicular distance from the pivot to the line of action of the force, in metres, m.

Question 30

If an object is balance..... (moments and pivots)

Answer 30

the total clockwise moment about the pivot = the total anticlockwise moment about that pivot

Question 31

leavers and gears can be used to...

Answer 31

- transmit the rotational effects of forces - magnify either the size of the applied force or the distance the force moves over

Question 32

what do levers do?

Answer 32

- increase the distance from the pivot at which the force is applied - less force is needed to get the same moment so its easier to do work

Question 33

what do gears do and how do they work?

Answer 33

they are used to transmit the rotational effect of a force from one place to another - their teeth interlock so the one turning causes another to turn in the opposite direction

Question 34

larger gears ...

Answer 34

-cause bigger moments - turn slower

Question 35

equation for distance, speed and time

Answer 35

distance = speed x time

Question 36

What's the difference between displacement and distnace?

Answer 36

Distance is a scalar quantity and displacement is a vector quantity. Distance is therefore the magnitude of displacement. Displacement is distance in a particular direction.

Question 37

What's the difference between speed and velocity?

Answer 37

Speed is a scalar quantity and velocity is a vector quantity. Speed is therefore the magnitude of velocity. Velocity is speed in a particular direction.

Question 38

What is the formula for acceleration?

Answer 38

change in velocity/time

Question 39

What is the equation for velocity?

Answer 39

change in displacement/time

Question 40

What is Lift force?

Answer 40

cause: aerofoil (wing) moving through fluid magnitude depends on: speed, density of fluid, wing shape direction: normal to wing