unit 3 - forces and pressure

Question 1

formula for moment

Answer 1

force* perpendicular distance from the point

Question 2

condition of equilibrium

Answer 2

the sum of the forces in one direction must equal the sum of the forces in the opposite direction

Question 3

what is the centre of mass

Answer 3

the point where the gravitational force acts

Question 4

the formula for Hooke’s law

Answer 4

F= ke

Question 5

what is the load

Answer 5

the force applied to the spring

Question 6

what is extention

Answer 6

the difference in length between stretch and unstretched length

Question 7

relation between extension and load

Answer 7

directly proportional until the point of elastic limit.

Question 8

what state is the spring in if it is in the state of elastic limit

Answer 8

the spring is permanently stretched without loads

Question 9

formula for pressure

Answer 9

P = F/A

Question 10

unit for pressure

Answer 10

pascal

Question 11

pressure in liquid

Answer 11

pgh

p is density

Question 12

what liquid do barometers have

Answer 12

mercury

Question 13

what is the space at the top of the barometer

Answer 13

vacuum

Question 14

what does manometer measures

Answer 14

pressure difference

Question 15

the formula for Boyle’s law

Answer 15

p1v1 = p2v2

Question 16

relation to volume and pressure

Answer 16

inverse proportion

Question 17

why do pressure increase when the volume halves( decreases)

Answer 17

there are now twice as many molecules in the area so the impact of molecules bouncing the wall has doubled