A stream of water of density ρ, cross-sectional area A and speed v strikes a wall that is perpendicular to the direction of the stream, as shown in the figure. The water then flows sideways across the wall. The force exerted by the stream on the wall is
A. ρv2A
B. ρvA/2
C. ρghA
D. v2A/ρ
E. v2A/2ρ
(GR0177 #57)
Solution:
Dimensional analysis:
Force has unit Newton = kg m/s2
The only choice has the right unit of force is choice A = (kg/m3)(m/s)2(m2) = kg m/s2
Answer: A
No comments :
Post a Comment