momentum

Question 1

what is the principle of the conservation of momentum?

Answer 1

total momentum before = total momentum after in a closed system where no external forces act

Question 2

what is newtons 1st law?

Answer 2

an object will remain at rest or continue moving with constant velocity unless acted on by a resultant force

Question 3

what does a closed system mean?

Answer 3

no external forces

Question 4

what is the formula for change in momentum?

Answer 4

change in momentum = force x time

Question 5

what is the formula for force?

Answer 5

force = change in momentum/ time

Question 6

what is newtons 3rd law?

Answer 6

object a pushes on object b and object b pushes on object a with an equal opposite force

Question 7

what 3 things must happen in order for newtons 3rd law to take place?

Answer 7

must be the same type of force, act on different objects and act in different directions

Question 8

what is the formula for change in momentum? (momentum)

Answer 8

final- initial

Question 9

what are the 4 key points for safety?

Answer 9

1) write equation
2) increase time taken to stop
3) to change the same momentum the force needs to be smaller as time is greater
4) prevents injury

Question 10

what is momentum measured in?

Answer 10

kgm/s

Question 11

is momentum a scalar or a vector?

Answer 11

vector because it has magnitude & direction

Question 12

what does the + or - sign show with a momentum value?

Answer 12

the direction

Question 13

what does the value of the momentum show?

Answer 13

the magnitude

Question 14

what does a + sign show for the momentum?

Answer 14

the direction is up or right

Question 15

what does a - sign show for the momentum?

Answer 15

the direction is down or left

Question 16

what equipment is needed for the investigation of momentum?

Answer 16

• linear tracks with 2 carts
• light gates, interface & computer
• electronic balance
• pasco file 1.05

Question 17

what do forces cause objects to do?

Answer 17

• change shape
• change speed
• change direction

Question 18

what is the formula for resultant force?

Answer 18

resultant force = mass x acceleration

Question 19

why does Newton’s third law apply to the conservation of momentum?

Answer 19

it is Newton’s third law pairs that cause the momentum to change

Question 20

what is change in momentum also called?

Answer 20

impulse

Question 21

to change momentum over a longer time…

Answer 21

a smaller force is needed

Question 22

to change momentum over a shorter time…

Answer 22

a larger force is needed

Question 23

how do crumple zones prevent injury?

Answer 23

• force = change in momentum/ time
• crumple zones increase the time taken to stop
• to change the same momentum, the force needs to be smaller as time is greater
• prevents injury

Question 24

the conservation of momentum always applies when…

Answer 24

no external forces act

Question 25

what does the conservation of KE always depend on?

Answer 25

depends on the collision

Question 26

elastic collisions…

Answer 26

total KE before = total KE after

Question 27

inelastic collisions:

Answer 27

total KE before > total KE after