Question

Which pair of quantities represent scalar
quantities?
(1) displacement and velocity
(2) displacement and time
(3) energy and velocity
(4) energy and time

Answer 1

Vector quantity have magnitude along with certain direction

Where as scalr quantity don't

Lets go for option elimination

1)Displacement and velocity

We say displacement as initial - final and has sign of positive negativ... There is certainly a direction involved so its a vector in its contrast distance is scalar quantity

Same with velocity it has direction along which path it goes along with magintude having negative positive value or i,j,k component of velocity or may be velocity towards North south etc.. So velocity is also a vector quantity in its contrast speed is scalar quantity

2)displacement and time

Again displacement a vector

Time doesn't have a direction (Not going much in mordern theory of seeing it as 4 coordinate of dimension we will make it simple)

So time is scalar

3)Energy and velocity

Energy when considerd have magnitude as 12ev 10joule etc not always goes with direction so a scalar but

Velocity a vector quantity

4)Energy and time

Yes here both pair we see are of scalar quantity and hence our answer.