QUESTIONS+AND+ANSWERS

For Q. For question 6,wouldn't the acceleration be positive since reference direction is down?

A. But then wouldn't the time be negative....I think you have to make the acceleration negative in order for it to work out. A. I just redid the question... the acceleration would be positive... my answer was wrong before because it is impossible for the balls to meet before 1 second had passed because the second ball had not even been thrown yet.

Q. Did you guys get the same answer for #5... how do we know which time value to use?

A: We use the first time value because that is when they first meet/collide. ALSO, #6 is wrong. You did not expand (t-1)^2 properly. You're suppose to have 1/2(-10(t^2-2t +1).