forces

Question 1

examples of contact forces

Answer 1

frictional force
tension force
drag force/air resistance
normal force
applied force

Question 2

surfaces friction work on

Answer 2

all states of matter

Question 3

what happens when friction causes things to heat up?

Answer 3

it restricts movement

Question 4

what way does friction move

Answer 4

opposite direction

Question 5

factors affecting frictional force

Answer 5

• roughness of the surfaces in contact
• magnitude of the forces pressing the surfaces together
• independent of the area of contact

Question 6

ways to reduce friction

Answer 6

apply lubricant
use streamlined shapes
use ball bearings
smooth surfaces

Question 7

non contact forces

Answer 7

gravitational force
magnetic force
electrostatic force

Question 8

what are electromagnets used for?

Answer 8

separate iron and steel from scrap metal piles

Question 9

uses of magnetic force in transportation

Answer 9

magnets in the train and track repel and lift the train a few centimeters above the track; friction is reduced; allows the train to move fast

Question 10

force acting on positive and negative charges

Answer 10

electrostatic force of attraction

Question 11

force acting on the negative charges

Answer 11

electrostatic force of repulsion

Question 12

what are the electric charges that do not flow in an electric circuit called?

Answer 12

static electricity

Question 13

weight and mass difference on moon and earth

Answer 13

the weight of an object on the moon is 1/6 its weight on earth while the mass of an object is the same everywhere.

Question 14

what is the space surrounding the earth where gravity is experienced called?

Answer 14

gravitational field

Question 15

equation relating mass and weight

Answer 15

w = m * g

Question 16

equation for pressure

Answer 16

Pa = N / m2

Question 17

what is speed?

Answer 17

a measure of how fast someone or something moves

Question 18

SI unit of speed

Answer 18

m/s

Question 19

equation for speed

Answer 19

speed = distance / time

Question 20

how is the resultant force represented?

Answer 20

double arrow

Question 21

how can pressure be increased?

Answer 21

decreasing area

Question 22

how can pressure be decreased?

Answer 22

increasing area

Question 23

factors that affect liquid pressure

Answer 23

liquid depth

liquid pressure

Question 24

what happens when we go higher?

Answer 24

air pressure decreases

Question 25

what is the air pressing on us in all directions known as?

Answer 25

atmospheric pressure

Question 26

why do underwater vehicles be very strong to withstand the water pressure?

Answer 26

the water pressure deep in the ocean is very strong

Question 27

why is the dam thicker at the bottom than at the top?

Answer 27

liquid pressure increases with depth. the pressure at the bottom of the reservoir is greater than at the top. The dam is thicker at the bottom to withstand the greater pressure.

Question 28

answering tech for water pressure

Answer 28

( recall fact ) + ( relate back to question )

Question 29

answering tech for force

Answer 29

( highlight the variable that has changed ) + ( relate back to formula and effect on pressure ) + ( highlight effect of change )

Question 30

why is water delivered to and stored in tanks at the top of most high rise buildings?

Answer 30

causes water in pipes below the tanks to be at a high pressure and ensures that water flows to the units below

Question 31

changes in air pressure

Answer 31

- squashing a juice box - hold a suction cup on the wall - cause difficulty breathing

Question 32

describe squashing a juice box

Answer 32

- lower air pressure in straw | - higher atmospheric pressure outside the straw pushes the liquid up

Question 33

describe suction cup on wall

Answer 33

-atmospheric pressure acting on the suction cup holds it tightly on the wall

Question 34

describe how force causes difficulty in breathing

Answer 34

an aircraft can fly at great heights where the air pressure is low. air is pumped into the aircraft so that the air pressure inside is similar to that near the ground. without this, passsengers will have difficulty breathing