Calculating Mass Ratio in Collision of Two Carts

[bigsaucy]

Two carts each 12 cm long travel toward each other on a frictionless air glider track. The first cart on the left has an initial velocity of 18 cm/s toward the other cart that is stationary. The carts then collide. The cart on the left has a new velocity of -4cm/s and the stationary cart now has a velocity of 8 cm/s. Calculate the ratio of m1/m2 where m1 and m2 are the masses of the two carts. (momentum is conserved in the system)

I used the fact that momentum is conserved in the system to write the expression:

P final = P initial

or in other words, since initially only the cart on the left is moving, 18m1 = -4m1 + 8m2

which whne solved leads to the expression 0.36 = m1/m2; the book however says the answer is 1/2.

Pls help?

 

[Fewmet]

Two carts each 12 cm long travel toward each other on a frictionless air glider track. The first cart on the left has an initial velocity of 18 cm/s toward the other cart that is stationary. The carts then collide. The cart on the left has a new velocity of -4cm/s and the stationary cart now has a velocity of 8 cm/s. Calculate the ratio of m1/m2 where m1 and m2 are the masses of the two carts. (momentum is conserved in the system)

I used the fact that momentum is conserved in the system to write the expression:

P final = P initial

or in other words, since initially only the cart on the left is moving, 18m1 = -4m1 + 8m2

which whne solved leads to the expression 0.36 = m1/m2; the book however says the answer is 1/2.

Pls help?

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