Physics (Essay) Paper 2 WASSCE (PC), 2020

Question 1

 

 

A physical quantity Q is given by the expression Q = ½ pv2, where  is density and v is velocity.
(a)        Determine the dimensions of Q.                                                        
            (b)        What physical quantity does Q represent?    

 

        

 

This was a popular question among candidates. The questions tested the knowledge of dimensions. Majority of the candidates performed poorly because they failed to show the symbol that indicates intention to determine dimensions. For example, [v2] = L2 T-2.



The expected response is as stated below:

            (a)        Dimensions of Q 
[ℓ] = ML-3
[v2] = L2 T2
[Q] = ML-1 T-2


(b)        The physical quantity represented by Q

Pressure