Question

Suppose all the surfaces in the previous problem are rough. The direction of friction on B due to A (a) is upward

Answer 1

Answer: Is upward

Explanation:

At equilibrium the weight of block B (Downward force) has to be balanced by an upward force which is the force of friction applied by block A on B.  

Answer 2

$<b>Now, (a). We know volume rate of the flow does not depends upon the the height of the pipe, since pipe.</b>$

∴ Velocity of the fluid will remains unchanged.

∴ (a). At A,

$<b>Area × Velocity = 1 cm³/s.</b>$

4/100 cm² × Velocity = 1

∴ Velocity = 25 cm/seconds.

________________________

(b). At B,  

Area × Velocity = 1 cm³/s.

2/100 × Velocity = 1

$<b>Velocity = 50 cm/seconds.</b>$

________________________

(c). Pressure difference, will be affected, this is because, there will be the gravitational work also which will be included.

$<b>Using the Bernoulli's equation,</b>$

      Using the Bernoulli's Equation,

P₁ + h₁ρg + 1/2 ρv₁² = P₂ + h₂ρg + 1/2 ρv₂²

∴ P₁ - P₂ = 1/2 ρ(v₂² - v₁²) + ρg(h₂ - h₁)

∴ P₁ - P₂ = 1/2 × 1 × (50² - 25²) + 1 × 1000(15/16)

∴ P₁ - P₂ = 937.5 + 937.5

∴ P₁ - P₂ = 1875 dyne/cm² or 187.5 Pa.

$<b>Hence, the pressure difference is 187.5 Pa.</b>$  

Hope it helps.