Answer:
7,79 seconds
Explanation:

You need to use the acceleration formula. A is acceliration,
is change in velocity and t is time.
You need to multiply the formula with t and divide by a and you get
a*t=
t=
/a
after that you just need to insert the numbers
change in velocity is 76.4 minus 0.
acceliration is gravitational acceleration which is 9.81.
After that you get
t=76.4/9.81
t= 7,787971458 s
Answer:
Explanation:
I can tell you what the answers for the middle column are, but if you don't know how to solve total energy problems, they won't make any sense to you at all.
First row, KE = 0
Second row, KE = 220500 J
Third row, KE = 183750 J
Fourth row, KE = 205800 J
That's also not paying any attention to significant digits because your velocity only had 1 and that's not enough to do the problem justice. I left all the digits in the answer. Round how your teacher tells you to.
We have no idea. We need to examine the experimental set-up. You've given us no information, except that there may have been some sort of collision.