The boundary-layer thickness, δ, on a smooth flat plate in an incompressible flow without pressure gradients depends on the freestream speed, U, the fluid density, rho, the fluid viscosity, μ, and the distance from the leading edge of the plate, x. (a) Express these variables in dimensionless form and (b) calculate dimensionless parameter (proportional to x) with x = 0.142 m, rho = 225 kg/m3, U = 0.133 m/s, μ = 0.2 × 10-4 N-s/m2

answer; /// the above statement is (true);

1 a

2 b

3 b

4 d

5 d

6 d

explanation:

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s