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1. You head across the Battle River in your boat with a velocity of 8.0 m/s, south. The river is flowing at 2.8 m/s, east.

a. Make a sketch indicating both velocity vectors. Show the resultant vector.

*I've done this and I'm faily certain what I have is correct.*

b. Determine the magnitude and direction of the resultant velocity vector.

*I got an answer of 8.5 m/s (which, again, I'm fairly certain is correct) what I don't get, is how to find the direction of the resultant velocity vector. I tried it and got a rather bizarre answer.*

c. Assume that you and your boat have a total mass of 192 kg. Calculate the magnitude and direction of the momentum of you and your boat as you cross the river.

*I calculated the momentum to be 1632 kg*m/s. Again, that seemed pretty straight forward to me. I'm lost on the direction again though. I believe it would be the same as the direction of the resultant vector?*

2. A railway car with a mass of 8.30 x 10^4 kg is moving west at 6.25 m/s when it collides with another car with a mass of 9.64 x 10^4 kg moving east at 7.00 m/s. The two freight cars join together at impact.

a. What is the common velocity of the two cars after they join together?

*I got an answer of 0.870 m/s, East.*

b. Calculate the magnitude of the impulse provided to each freight car in this collision

*.*

I used mvf-mvi... I got the same answer of 5.91 x 10^5 for both cars... does that seem right?

I used mvf-mvi... I got the same answer of 5.91 x 10^5 for both cars... does that seem right?

c. Now calculate the percent loss of kinetic energy.

*I used % Ek lost = ((deltaEk)/(Ekinitial))... I'm not sure if that's correct though.*

3. Sara's favourite game is marbles. Her favourite marble is a large steel marble with a mass of 32 g. She shoots it with a speed of 24 cm/s directly at a staionary, smaller glass marble with a mass of 15 g. After the collision, the glass marble moves ahead with a speed of 30 cm/s.

a. Determine the resulting speed of the steel marble.

I got an answer of 0.23 m/s. Again, I'm not positive that's correct.

I got an answer of 0.23 m/s. Again, I'm not positive that's correct.

b. If this collision had been perfectly elastic, determine the resulting velocities of both the glass and the steel marbles.

*I don't really know how to do this. I understand that elastic means there isn't a change in the kinetic energy, but that's about all I understand.*