relative velocity please help exam tom.
posted by candance .
the paper delivery boy tires to throw the paper ubti your narrow driveway without slowing down. his pickup truck travels at 10 mph and he throws the paper at 20 mph just as the truck passes the drive way.
a) in what direction should he throw the paper in order for it to land in the driveway?
b)what is the paper's speed relative to the ground?
I have no idea on how to solve this ground. i know it's relative velocity and i tried drawing the picture but i still need help.
for a) i'm guessing he should throw the paper forward because the truck is moving.

For the paper to go through the air perpendicular to the street and the front of the house, it should be thrown backward relative to the car, with a relative velocity of 10 mph. The forward component of motion relative to the car will be
sqrt [(20)^2  (10)^2] = 17.3 mph
That will also be the speed relative to the ground, since the velocity component in that direction is the same relative to car or ground.
As for the angle it is thrown, relative to the car, it is cos^1 (10/20) or 120 degrees off the direction of motion of the car. 
a swimer covers ditance d in time t1 in to and rro motion , he travels ditance 2d in still water in time t3 and covers distance d upstream and down stream in t2 prove that squre of t1=t2.t3