# When do we use dot product and when do we use cross product? [closed]

I actually dont understand that when do we use cross product and when to use dot product ……it is very difficult to remember that a torque is cross product and work done is dot product. please tell me the reasons behind these so that i can understand the concept not just blindly memorize?

• Torque is a vector (an axial vector if we're pedantic), while work is a scalar. Do you wish to ask why that is so, or do you understand it? Because that's enough information to work out which product to use.
– J.G.
Commented Aug 17, 2023 at 10:03
• Yeah please explain more to me…. Commented Aug 17, 2023 at 10:05
• A torque cannot be completely defined without giving it a sense of rotation i.e. clockwise vs anticlockwise. So torque couldn't be defined using a dot product since that gives a scalar output.
– AVS
Commented Aug 17, 2023 at 10:47
• Why is work a scalar: physics.stackexchange.com/questions/418187/…
– AVS
Commented Aug 17, 2023 at 10:49
• Commented Aug 17, 2023 at 12:17