- #1
mmiller39
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Why isn't this working! 2D Kinematics
Here is the problem:
Relative to the ground, a car has a velocity of 18.2 m/s, directed due north. Relative to this car, a truck has a velocity of 22.9 m/s directed 47.2 ° south of east. Find the (a) magnitude and (b) direction of the truck's velocity relative to the ground. Give the directional angle relative to due east.
For a) I found the answer as follows (which is correct)
V of T in relation to G (Vtg) = V of T in relation to C (Vtc) + V of C in relation to G Vcg.
The x factor looks like this:
Vtgx = Vtc + Vcg
22.9 cos 47.2 + 0 = 15.6
Y factor:
Vtgy = Vtc + Vcg
-22.9 sin 47.2 = 1.39
Vtg = Sqrt (Vtgx^2 + Vtgy^2) = 15.7 <-------the Right answer
For b) I did
tan^-1 y/x, but I keep getting the wrong answer. What is going on. I keep getting 5.07, and this is incorrect!
Here is the problem:
Relative to the ground, a car has a velocity of 18.2 m/s, directed due north. Relative to this car, a truck has a velocity of 22.9 m/s directed 47.2 ° south of east. Find the (a) magnitude and (b) direction of the truck's velocity relative to the ground. Give the directional angle relative to due east.
For a) I found the answer as follows (which is correct)
V of T in relation to G (Vtg) = V of T in relation to C (Vtc) + V of C in relation to G Vcg.
The x factor looks like this:
Vtgx = Vtc + Vcg
22.9 cos 47.2 + 0 = 15.6
Y factor:
Vtgy = Vtc + Vcg
-22.9 sin 47.2 = 1.39
Vtg = Sqrt (Vtgx^2 + Vtgy^2) = 15.7 <-------the Right answer
For b) I did
tan^-1 y/x, but I keep getting the wrong answer. What is going on. I keep getting 5.07, and this is incorrect!