## jahnavi 2 years ago Work done on a body is a vector quantity? True or False?

1. Qasim_Ahmed

true my dear caouse it calculated by $W = F \times X$ when both force and the distance X are vectors and as you know multiplying a vector by a vector gives an other vector which is normal on both of them .. greeting mate

2. gleem

Sorry but work is a scalar quantity. there are two types of vector "multiplications" Dot or scalar product and cross or vector product.

3. jahnavi

I think i agree with gleem that work is a scalar quantity,but i did not undustand the second half of the ans.

4. gleem

The dot production is equal to the product of the magnitude of the two vectors being multiplied times the cosine of the angle between them. It is thought of as the projection of the first vector in the direction of the second times the magnitude of the second. In the case of work it is the projection of the force in the direction of the displacement times the displacement. The vector product is the product of the magnitudes of the vectors times the sine of the angle between them with the result being a vector of this magnitude and point perpendicular to the first two vectors with a direction which is found by using your right hand pointing your fingers in the direction of the first vector rotating your fingers in to the second vector with you thumb pointing in the direction of the product.|dw:1356704388046:dw| Example of cross product is torque ie L= F x R where F is a force and R is a displacement form the point the force is applied to the point about which the force is pivoting.