Question

4. Say Russell Wilson has to throw Doug Baldwin a pass 50 meters in 2 seconds. Assume no air or spin of the ball and use 3 - 10 m/s. Use 1.8 meters for the ball height lxth right after it is thrown, and right before it is caught. (a) What is the initial speed Wilson has to throw the hall at? and (b) what is the angle he has to throw the ball at? Bussine Ram Baldwin neglect air, neglect spin meseci ar meget son 2

Answer 1

Let us assume the velocity of the throw is v.

So, the horizontal velocity is

V = v cos

The horizontal distance traveled is

dr = 50 m

And the time of the flight is

t=2s

The acceleration in the horizontal direction is zero. So, the horizontal velocity can be given by

V = · = 25 m/s

Now, the initial vertical velocity is

Uy = usin

The acceleration in the vertical direction is

dy = -9 = -10 m/s2

The vertical displacement of the ball is

dy = 1.8 – 1.8 = 0 m

The equation of motion is

dy = uyt + 1 7 ayt?

= dy = v sin 8 x 2 -- 10 x 22 So

usin 8 x 2 = 20

usin = 10

uy= v sin = 10 m/s

We have

Vj = cos 0 = 25 m/s

So, the initial speed is

v = V0 + u} = 252 + 102 = 26.93 m/s

And the angle is

U