A mechanics question about work and vectors

[iwsdw]

this year i started studying physics, so this question might be easy but i couldn't do it... i'll be happy if you help me.

''A constant force (5N)i-7(N)j is applied on an object and it moves. The total displacement of the object is l=(3)i+(6)j+(3)k. Find the angle between the force and the displacement.''

 

[lewando]

What specifically do you need help (or are having trouble) with? Please elaborate.

 

[iwsdw]

I don't know how to find the angle. How can I use the displacement information to find the angle?

 

[Chestermiller]

How is the dot product of two vectors related to the angle between them?

 

[iwsdw]

Ah yes! Thank you very much. ^^