1)after catching the ball, sarah throws it back to julie. however, sarah throws it too hard so it is over julie's head when it reaches julie's horizontal position. assume the ball leaves sarah's hand a distance 1.5 meters above the ground, reaches a maximum height of 8 m above the ground, and takes 1.505 s to get directly over julie's head.

what is the speed of the ball when it leaves sarah's hand? (the answers is not 16.67m/s)

2)how high above the ground will the ball be when it gets to julie? (the answers is not 7.744)

1)

2)

Explanation:

Projectile Motion

When an object is launched near the Earth's surface forming an angle with the horizontal plane, it describes a well-known path called a parabola. The only force acting (neglecting the effects of the wind) is the gravity, which acts on the vertical axis.

The heigh of an object can be computed as

Where is the initial height above the ground level, is the vertical component of the initial velocity and t is the time

The y-component of the speed is

1) We'll find the vertical component of the initial speed since we have not enough data to compute the magnitude of

The object will reach the maximum height when . It allows us to compute the time to reach that point

Solving for

Thus, the maximum heigh is

We know this value is 8 meters

Solving for

Replacing the known values

2) We know at t=1.505 sec the ball is above Julie's head, we can compute

365.25 earth days are in the year of a light year