please help me with these problems....i am really confused??

Question

1. a car accelerates constantly. it started at 10 m with a velocity of 15 m/s and ended at 40 m with velocity of 60 m/s, what was the acceleration?
2. a person falls out of a hot air balloon. eyewitnesses reported that it took the person 5 secs. to hit the ground. what was the person's velocity just before they hit the ground?
3. a car with an intitial velocity of 30 m/s slammed on the brakes and skidded to a stop. if the skid marks created by the tires were 15 m long, and the car experienced constant acceleration, what was the car's acceleration while the brakes were applied.
4. if the driver of a car applied the brakes so that the car had an acceleration of -3m/s^2, and the car started out with a velocity of 50 m/s, what was the distance required for the car to come to a stop?

use one of the following equations:
1. V=Vo+at 2. X=Xo+Vo t+1/2at^2
3. v^2=Vo^2+2a(X-Xo)

thank you if you do help......

i just need to know what informations are given.

Answer 1

Look at the 1'st one.
V0 = 15
V = 60
X0 = 10
x = 40
Now, plug those into the 3'rd equation
60²=15² + 2a(40-10) or
3600 = 225 + 2a(30)
3375 = 60a
56.25 = a

Now -you- work the rest of them. Just write down what you know and the equation that you need will be obvious.

Doug