Two forces of 4 N and 5 N act on an object and their corresponding force vectors have a dot product of 8. What is the angle between the vectors?
a) 66.42°
b) 27.27°
c) 23.58°
d) 62.73°
We have
cos (theta) = dot product / [ product of the vector magnitudes ]
cos (theta) = 8 / [ 4 * 5 ]
cos (theta) = 8 / 20 = 2/5
To find theta
arccos ( 2/5) = theta = 66.42°
+956 
