physics help - To all you smart people

[Edex]

A.) A 8 kg fish swimming 5 m/s swallows an absent minded 1 kg fish at rest, as shown below. What is the speed of the large fish immediately after lunch?

B.) What would its speed be if the small fish were swimming towards it at 4 m/s?

 

[badassjuly18]

4.6 im guessing

 

[Made in Heaven]

Shit, I ain't got time for that. Even though I could solve it

 

[BlacLord™]

A 8 kg fish swimming 5 m/s swallows an absent minded 1 kg fish at rest, as shown below. What is the speed of the large fish immediately after lunch?

mass x velocity = momentum

we find the total momentum of the system first.

and then we calculate the new speed of the combined mass for Question 1:

8 x 5 = 40 Momentum of big fish

1 x 0 = 0 momentum of small fish

total momentum = 24

new mass = 9

24/9 = 2.66

new speed = 2.66m/s

Use my example to do the second one.

 

[Mattyj420]

A 8 kg fish swimming 5 m/s swallows an absent minded 1 kg fish at rest, as shown below. What is the speed of the large fish immediately after lunch?
[FONT=Helvetica Neue, Helvetica, Arial, san-serif]
[/FONT]mass x velocity = momentum

we find the total momentum of the system first.


and then we calculate the new speed of the combined mass for Q 1

8 x 5 = 40 Momentum of big fish

1 x 0 = 0 momentum of small fish

total momentum = 24

new mass = 9

24/9 = 2.66

new speed = 2.66m/s

Use my example to do the second one.

.


Use this

 

[Rainbow Dash]

You simply use the CoM formula.

m1 * v1 = m2 * v2

8 * 4 = (8 + 1) * v2

24 = 9 * v2

24/9 = v2

2.66 m/s = v2

Basically the same thing as above, except paraphrased.