Engineering Questions with Answers - Multiple Choice Questions

# MCQs on Horizontal and Inclined Plane Surface Submerged in a Liquid

1 - Question

Find the total pressure on a rectangular plate of dimensions 2×3 m immersed in a fluid of specific gravity 0.65 at a depth of 6 m from the surface.
a) 22.9 N/cm2
b) 45.8 N/cm2
c) 11.5 N/cm2
d) None of the mentioned

a
Explanation: Total pressure, F=w*a*y
=9.81*650*6*2*3
=22.9 N/cm2.

2 - Question

Find the total pressure on a circular plate of diameter 3 m immersed in a fluid of specific gravity 0.75 at a depth of 5 m from the surface on a planet having acceleration dueto gravity 7 m/s2.
a) 18.5 N/cm2
b) 37 N/cm2
c) 9.25 N/cm2
d) None of the mentioned

a
Explanation: Total pressure, F=w*a*y
=7*750*π*1.5*1.5*5
=18.5 N/cm2.

3 - Question

A rectangular plate surface 3m wide and 5m deep lies in fluid of specific gravity .9 such that its plane makes an angle of 45⁰ with water surface, upper edge 3m below free water surface. Determine the total pressure.
a) 86.5 N/cm2
b) 173 N/cm2
c) 43.25 N/cm2
d) None of the mentioned

a
Explanation: Total pressure, F=w*a*ŷ=w*A*(y+dsinθ)=9.81*900*15*(3+5sin45)
=86.5 N/cm2.

4 - Question

A rectangular plan surface 5 m wide and 7 m deep lies in water in such a way that its plane makes an angle 60⁰ with the free surface of water. Determine the total pressure force when the upper edge is 3 m below the free surface.
a) 311.15 N/cm2
b) 622.3 N/cm2
c) 155.5 N/cm2
d) None of the mentioned

a
Explanation: Total pressure, F=w*a*ŷ=w*A*(y+dsinθ)=9.81*1000*35*(3+7sin60)=311.15 N/cm2.

5 - Question

A circular plate 5.0 m diameter is immersed in such a way that its greatest and least depth below the free surface are 3 m and 1 m respectively. determine the position of the centre of pressure.
a) 2.5 m
b) 5 m
c) 4.5 m
d) 6 m

a
Explanation: centre of pressure, ŷ=I*sin²θ/Aĥ + ĥ
…….ĥ=(y+dsinθ)
=3.142*2.54*sin²23.58/3.142*2.52*(1+2.5sin23.58)+*(1+2.5sin23.58)
=2.5 m.

6 - Question

For an inclined plate the pressure intensity at every point differs.
a) True
b) False

a
Explanation: Due to inclination the depth of every point is different from the free liquid surface. Hence, the pressure intensity varies with depth.

7 - Question

The pressure intensity for a horizontal plate is maximum on the surface of the earth and decreases as we move further away from the surface of the earth either downward or upward.
a) True
b) False

a
Explanation: As we move away from the surface of the earth either downward or upward g decreases, w decreases. Hence pressure intensity decreases.

8 - Question

For an inclined plane for which position, maximum total pressure acts on it.
a) Horizontal
b) Vertical
c) Inclined
d) None of the mentioned

b
Explanation: Total pressure, F=w*a*ŷ=w*A*(y+dsinθ)
For vertical plate, θ=90⁰
Hence, total pressure is maximum.

9 - Question

The total pressure or pressure intensity is zero for any point on inclined surface in space.
a) True
b) False

a
Explanation: Total pressure, F=w*a*ŷ
In space, w=0 as g=0
Hence, f=0.

10 - Question

In case of spherical bodies with uniform mass distribution, what is the position of center of pressure relative to centre of gravity.
a) Above
b) Below
c) Coincides
d) None of the mentioned