I did it the same way as Kaseita for the cannon ball question by using the formula:
v^2= u^2 + 2as
I think the problem with using:
1) a = (v - u)/t
2) t = s/v
is actually in the second equation. The "v" in the second equation is not equivalent to the "v" in the first equation. The "v" in the first equation represents the final speed at which the capsule exits the cannon, while the "v" in the second equation is really the mean (average speed) at which the capsule travels through the cannon, from 0 to the given speed.
As for the multiple choice, my answers were precisely the same as AlexZ. Question 14 was a guess though. Anyone know for sure what answer it is? I put B.
The exam was really easy, but a little too easy for its own good. I think the average of the state is going to be really high so I hope that doesn't mean we get scaled down.
v^2= u^2 + 2as
I think the problem with using:
1) a = (v - u)/t
2) t = s/v
is actually in the second equation. The "v" in the second equation is not equivalent to the "v" in the first equation. The "v" in the first equation represents the final speed at which the capsule exits the cannon, while the "v" in the second equation is really the mean (average speed) at which the capsule travels through the cannon, from 0 to the given speed.
As for the multiple choice, my answers were precisely the same as AlexZ. Question 14 was a guess though. Anyone know for sure what answer it is? I put B.
The exam was really easy, but a little too easy for its own good. I think the average of the state is going to be really high so I hope that doesn't mean we get scaled down.