Question

A boat floats south on the Amazon River at a speed of 6 m/s. The boat and passengers have a combined mass of 540 kg.

a. What is the momentum of the boat? (Remember, momentum is a vector quantity.)

b. The passengers paddle backward, reducing the speed to 4 m/s. What was the impulse applied to the boat by the paddling?

Answer 1

Do you know the formula for momentum?

Answer 2

@zarkam21

Answer 3

p=mv

Answer 4

so 540*6?

Answer 5

Yes, and make sure to remember what they noted in (a)

Answer 6

so 3240kg m/s

Answer 7

because momentum is a vector quantity

Answer 8

What must you include then?

Answer 9

3240kg m/s south

Answer 10

Correct

Answer 11

Now for (b), what direction are the passengers paddling in?

Answer 12

backwards?

Answer 13

Yes, North.

Now, do you know what impulse is?

Answer 14

Isn't it Newtons Second Law of Physics

Answer 15

Impulse is also the change in momentum

Answer 16

mhm

Answer 17

\[J = F \times \Delta T = m \Delta V\]

Answer 18

That's the formula for impulse. We can disregard Force multiplied by Time.

Answer 19

j=540*4
j=1620

Answer 20

Incorrect

Answer 21

Can you take a guess as to why?

Answer 22

well the delta sign

Answer 23

What does that sign mean?

Answer 24

change in velocity

Answer 25

What was the change in velocity for this problem?

Answer 26

6-4=2?

Answer 27

\[\Delta V = V _{f} - V _{i} = 6 - 4 = 2m/s\]

Answer 28

Yes, so what would our setup be for impulse?

Answer 29

540*2

Answer 30

j=540*2
j=1080

Answer 31

There you go

Answer 32

the unit would be n right?

Answer 33

Use the units of mass times velocity (kg times m/s)

Answer 34

so 1080 kg m/s

Answer 35

Yes

Answer 36

=) Thank you so much

Answer 37

No problem