Acceleration Vector Word Problem

[Retweetfire]

Homework Statement

Famous quarterback Fleet O. Floote is attempting a quarterback draw by running up the middle toward his goal line at 4.6 m/s. A linebacker hits him squarely, and their combined final velocity is 3.8 m/s at an angle of +120.° from the quarterback's original direction. The time it took to change direction at impact was 0.20s. Choose an appropiate horizontal coordinate system and calculate the average acceleration vector of the quarterback during the tackle.

Homework Equations

a = ΔvΔt

The Attempt at a Solution

v1 = 4.6 m/s 90.0°
v2 = 3.7 m/s 120.°

v1x = 0 m/s
v1y = 4.6 m/s

v2x = 3.7 cos 60° = 1.9 m/s
v2y = 3.7 sin 60° = 3.2 m/s

I have this, but I feel that I'm missing something.

 

[Chestermiller]

Please draw a diagram, and show it to us. Thank you.

It seems to me, if the new velocity direction is 120 degrees to the original direction, one of the new components has to be negative.

 

[BvU]

Hello rf,

at an angle of +120.° from the quarterback's original direction

Can you post a sketch and compare with what you (were going to) calculate ? Then complete your attempt ?

 

[Retweetfire]

Hello rf,

Can you post a sketch and compare with what you (were going to) calculate ? Then complete your attempt ?

 

[Chestermiller]

That's only at a 30 degree angle to the QBs original velocity. Did they really mean 120 degrees, or did they really mean 30 degrees?