Momentum of two balls collision question

AI Thread Summary
Two balls of equal mass collide, with one initially stationary and the other moving at 5.4 m/s. After the collision, the balls' velocities form angles of 33° and 43° with the original direction. The discussion involves setting up equations based on conservation of momentum in both x and y axes. A user successfully solved the equations using substitution to find the final speeds of the balls. The problem-solving approach proved effective, leading to a successful test outcome.
mvk1
Messages
13
Reaction score
1
Two balls of equal mass m undergo a collision. One ball is initially stationary. After the collision, the velocities of the balls make angles of 33° and 43° relative to the original direction of motion of the moving ball. If initial speed of moving ball is 5.4 m/s find the final speed.

What I've done:
In x axis:
M1V1+ M2V2= M1V1’+ M2V2’
M(5.4)+M(0)=M(V1’Cos33)+M(V2’Cos46)
5.4M= M( V1’Cos33+ V2’Cos46)
5.4= V1’Cos33+ V2’Cos46

In the y axis:
0= M1V1’+ M2V2’
0=M(V1’Sin33)-M(V2’Sin46)
(Dividing both sides by M)
0=( V1’Sin 33- V2’Sin46)
0= V1’Sin33- V2’Sin46i don't know what do do after this! please help!

HERES IMAGE OF PROBLEM WITH DIAGRAM:
http://i.imgur.com/NKSeA.jpg
 
  • Like
Likes Phil Ainao
Physics news on Phys.org
You have two equations and two unknowns. Solve them simultaneously. Try using the method of substitution. (Use one equation to express V1' in terms of V2'. Then substitute that into the second equation and solve for V2'.)
 
Doc Al said:
You have two equations and two unknowns. Solve them simultaneously. Try using the method of substitution. (Use one equation to express V1' in terms of V2'. Then substitute that into the second equation and solve for V2'.)

OMG THANKS YOU SO MUCH I DID IT RIGHT ON MY TEST!
PRETTY INTENSE BUT THANKS SO MUCH!
i found easier to use a,b for v1' and v2' made my life a lot easier
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Back
Top