# Solving Momentum Problems: Rocket, Crate & Cannon

• litto_0ne
In summary, the first conversation involved a problem where a rocket explodes into three pieces and the velocity of the third piece was found to be 510 m/s. The second conversation involved two people standing on a crate and jumping off, with the first person jumping off at a velocity of 36 m/s and the second person jumping off at the same velocity. The third conversation involved a cannon firing a shell and exploding into two fragments, with the distance between the two pieces being unknown. Further guidance was requested in solving the problem.
litto_0ne
Problems Shortened
1) Rocket fired up, when it reaches 300 m/s and 1000m, it explodes into three pieces. One contnues up at 450 m/s and the other continues east at 240 m/s. Third velocity?
used conservation of momentum with components
found that the velocity of the third piece had an x-component of -240 m/s and y-component of 450 m/s. solved and got 510 m/s. did i approach this problem correctly?
2) Two people standing on a crate on a frictionless frozen pond. One person weighs 75 kg, the other 45 kg and the crate 15 kg. They jump horizontaly from the top of the crate. Just after each jumps, the person moves away from the crate at 4 m/s relative to the crate.
a)What is the speed of the box if both jump off?
MVi = MVf
135(4) = 15(V)
V = 36 m/s
i have a feeling that i wdid that incorrectly
b)What is the speed the 75 kg jumps off and then the
45 kg person jumps off a few seconds later?
135(4) = 60V V= 9 velocity after one person
jumps
60(9) = 15V
V= 36
i also have a feeling that i did this one
incorrect since a and b are both the same
3)Cannon fires 100kg shell 60 degrees at 600 m/s. at highest point it explodes into two fragments (m1 = 2/5M and m2 = 3/5M), with an additional 10kJ of energy in the original horizontal direction. Whats the distance between the two pieces?
honestly for this one i am lost. i don't expect it to be solved, but could someone possible guide me through it? or get me started?
Thanks!

First: x-component was correct but y is wrong.

can anyone give me a clue in finding the y-component?

## 1. What is momentum and why is it important in rocket, crate, and cannon problems?

Momentum is a measure of an object's motion and is calculated by multiplying its mass by its velocity. In rocket, crate, and cannon problems, momentum is important because it helps us understand how these objects will behave and interact with each other during their motion.

## 2. How do you calculate the momentum of a rocket, crate, or cannon?

To calculate the momentum of a rocket, crate, or cannon, you need to know the mass and velocity of the object. The equation for momentum is: momentum = mass x velocity. Make sure to use consistent units when plugging in the values for mass and velocity.

## 3. What is the law of conservation of momentum and how does it apply to rocket, crate, and cannon problems?

The law of conservation of momentum states that the total momentum of a system remains constant if there are no external forces acting on it. In rocket, crate, and cannon problems, this means that the combined momentum of all objects involved before and after a collision or explosion will be equal.

## 4. How do you solve for unknown variables in momentum problems?

To solve for unknown variables in momentum problems, you can use the equation for momentum and rearrange it to solve for the desired variable. You can also use the law of conservation of momentum to set up equations and solve for unknowns using algebraic manipulation.

## 5. Can momentum be negative in rocket, crate, and cannon problems?

Yes, momentum can be negative in these problems. This indicates that the object is moving in the opposite direction of the chosen positive direction. It is important to pay attention to the direction of momentum when solving these problems to correctly interpret the results.

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