- #1

physicsgrouch

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**[SOLVED] Impulse of deflected ball**

**1. Recent studies have raised concern about `heading' in youth soccer (i.e., hitting the ball with the head). A soccer player `heads' a 0.421 kg ball, deflecting it by 50.0 degrees, and keeps its speed of 10.40m/s constant. (The deflection angle is the angle between the ball's initial and final velocity vectors.) What is the magnitude of the impulse which the player must impart to the ball?**

m = 0.421 kg

v[tex]_{}i[/tex] = -10.4 m/s

v[tex]_{}f[/tex] = 10.4 m/s at 50 degrees

**2. The equations**

impulse = [tex]\Delta[/tex]p = m(v[tex]_{}i[/tex]) - m(v[tex]_{}f[/tex])

so impulse = m(v[tex]_{}f[/tex] - v[tex]_{}i[/tex])

So I multiplied the mass by the change in velocity. Namely:

**3. The solution**

0.421 *{sqrt[ (10.40*sin50)^2 + (10.40*(cos50 +1))^2) ]}

So I got about 7.936. But this is wrong. What's up?