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Maths mechanics

A particle B of mass 0.3kg is moving with velocity (7i+4j)m/s when it collides with a stationary particle C of mass 0.5kg. immediately after the collision C moves with velocity (6i+0) m/s.

a) find the velocity of B immediately after the collision.
b) find the speed of B immediately after the collision
(edited 8 years ago)
how far did you get harry ?
Original post by harrybo6
A particle B of mass 0.3kg is moving with velocity (7i+4j)m/s when it collides with a stationary particle C of mass 0.5kg. immediately after the collision C moves with velocity (6i+0) m/s.

a) find the velocity of A immediately after the collision.
b) find the speed of A immediately after the collision


You must've learned the equation m1u1 + m2u2 = m1v1 + m2v2 right?
m1 is the mass of particle B
m2 is the mass of particle C
Can you tell me what v1,v2,u1 and u2 are? If so just plug them into the equation.
(edited 8 years ago)
You didnt mention a particle A but if you got your letters wrong you can just use conservation of momentum.
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harrybo6
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5
Original post by ComputerMaths97
You must've learned the equation m1v1 + m1u1 = m2v2 + m2u2 right?
m1 is the mass of particle B
m2 is the mass of particle C
Can you tell me what v1,v2,u1 and u2 are? If so just plug them into the equation.


i can tell you what i did but im not sure if im right! i did 0.3x(7i+4j) which i got
2.1i+1.2j = before momentum
after momentum =2.1i+1.2j = 0.3v + 0.5(6i) = 0.3v+3i
so i rearranged moving 3i over -0.9i+1.2j = 0.3v devided by 0.3
=-3i+4j
thats what i got for part a) but part b i have no clue i thought they were the same, so i just squared 3 and 4 then took the sqare number of that which got me 5
Reply 5
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harrybo6
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Original post by CheetahCurtis
You didnt mention a particle A but if you got your letters wrong you can just use conservation of momentum.


sorry didnt see that, thanks for letting me know:smile:
Original post by harrybo6
i can tell you what i did but im not sure if im right! i did 0.3x(7i+4j) which i got
2.1i+1.2j = before momentum
after momentum =2.1i+1.2j = 0.3v + 0.5(6i) = 0.3v+3i
so i rearranged moving 3i over -0.9i+1.2j = 0.3v devided by 0.3
=-3i+4j
thats what i got for part a) but part b i have no clue i thought they were the same, so i just squared 3 and 4 then took the sqare number of that which got me 5


Perfect!
(edited 8 years ago)
Reply 7
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harrybo6
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5
Original post by ComputerMaths97
Perfect!


Thank you:smile:

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