3.2

Question 1

weight

Answer 1

force exerted by earth on an object / force experienced by mass dues to a gravitational field

Question 2

normal contact force

Answer 2

force exerted by a surface on an object perpendicular to that object

Question 3

friction

Answer 3

force exerted by a surface on an object along the parallel direction to the surface opposing the direction of motion

Question 4

tension

Answer 4

force exerted by a stretched string/rope/cable/wire on a subject

Question 5

upthrust

Answer 5

force exerted by a fluid on an object that is totally or partly immersed

Question 6

drag

Answer 6

force exerted by a fluid on an object that is moving inside the fluid

Question 7

equation to find the horizontal component of the vector

Answer 7

xcosϴ

Question 8

equation to find the vertical component of the vector

Answer 8

xsinϴ

Question 9

mass

Answer 9

scalar quantity, how much matter is in a substance

Question 10

archimedes principal

Answer 10

upthrust= the weight of fluid displaced (whether or not something floats or sinks depends upon its density relative to water)

Question 11

centre of mass

Answer 11

single point that you can consider the whole weight of an object to act through. the object will always balance around this point

Question 12

how to find the centre of mass

Answer 12

symmetry or experiment : suspend object twice at two difference points and where the lines they hang through cross = centre of mass

Question 13

how do you know an object will be stable

Answer 13

wide base area and low centre of mass

Question 14

contact friction

Answer 14

friction between solid surfaces

Question 15

fluid friction

Answer 15

drag / air resistance

Question 16

things to remember about friction

Answer 16

oppose direction of motion, convert kinetic energy into heat

Question 17

terminal velocity

Answer 17

when friction equals driving force - friction will increase with speed until the friction prevents any further acceleration so a steady speed is reached

Question 18

what affects terminal velocity

Answer 18

viscosity of the liquid, size of the thing you are dropping, shape of object, mass of object

Question 19

density

Answer 19

a measure of the compactness of a substance mass/vloume

Question 20

pressure in a fluid

Answer 20

p=hPg h=depth of submersion, P=density of fluid,

Question 21

moment

Answer 21

Turing effect of a force , a force acting perpendicular to a distance from a pivot

Question 22

moment equation

Answer 22

m=f x distance from pivot

Question 23

couple

Answer 23

pair of forces of equal size which act parallel but opposite to each other

Question 24

torque of a couple=

Answer 24

size of one of the forces x perpendicular distance between forces