natural convection – involves change in density of the fluid with temperature, whereas
forced convection involves the mixing of hot and cold part of the fluid though some
external stirring, like a fan or pump
sharon kalunda answered the question on April 2, 2019 at 13:47
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The total weight of a car with passengers is 25,000N. The area of contact of each of the four
tyres with the ground is 0.025m2. Determine...
(Solved)
The total weight of a car with passengers is 25,000N. The area of contact of each of the four
tyres with the ground is 0.025m2. Determine the minimum car tyre pressure
Date posted:
April 2, 2019
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Answers (1)
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A block measuring 20cm x 10cm by 5cm rests on a flat surface. The block has a weight of 3N.
Determine the maximum pressure it exerts...
(Solved)
A block measuring 20cm x 10cm by 5cm rests on a flat surface. The block has a weight of 3N.
Determine the maximum pressure it exerts on the surface.
Date posted:
April 2, 2019
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Answers (1)
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The figure shows a liquid in a pail.
(Solved)
The figure shows a liquid in a pail.
Suggest a reason why pail manufacturers prefer the shape shown to other shapes
Date posted:
April 2, 2019
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Answers (1)
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Two immiscible liquids are poured in a container to the levels shown in the diagram below.
(Solved)
Two immiscible liquids are poured in a container to the levels shown in the diagram below.
If the densities of the liquids A and B are 1g/cm3 and 0.8g/cm3 respectively, find the pressure
acting upon solid C at the bottom of the container due to the liquids
Date posted:
April 2, 2019
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Answers (1)
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Figure below shows a measuring cylinder of height 30cm filled to a height of 20cm with water and the rest occupied by kerosene.
(Solved)
Figure below shows a measuring cylinder of height 30cm filled to a height of 20cm with water and the rest occupied by kerosene.
Given that density of water = 1000Kgm-3, density of kerosene = 800Kgm-3 and atmospheric pressure = 1.03x105 pascals, determine the pressure acting on the base of the container.
Date posted:
April 2, 2019
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Answers (1)
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The barometric height at sea level is 76cm of mercury while at a point on a highland it is 74cm of mercury. What is the...
(Solved)
The barometric height at sea level is 76cm of mercury while at a point on a highland it is 74cm of mercury. What is the altitude of the point? (Take g = 10m/s2 , density of mercury =
13600kg/m3 and density of air as 1.25kg/m3)
Date posted:
April 2, 2019
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Answers (1)
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State one factor that determines the depth to which mercury is depressed in a glass capillary tube.
(Solved)
State one factor that determines the depth to which mercury is depressed in a glass capillary tube.
Date posted:
April 2, 2019
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Answers (1)
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A bathroom shower has 200 holes each 2.5mm2 in area. Water flows from a pipe of cross-section
area of 15cm at 5m/s to the shower. Determine...
(Solved)
A bathroom shower has 200 holes each 2.5mm2 in area. Water flows from a pipe of cross-section
area of 15cm at 5m/s to the shower. Determine the speed of the spray.
Date posted:
April 2, 2019
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Answers (1)
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A piece of metal N of mass 2kg weighs 18N in water and 12N in liquid M. Determine the density of ;
(Solved)
A piece of metal N of mass 2kg weighs 18N in water and 12N in liquid M. Determine the density of ;
(i) The metal N
(ii) The liquid M
Date posted:
April 2, 2019
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Answers (1)
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A measuring cylinder contains 50cm3 of light oil at 0oC. When a lump of dried ice is placed in the oil, the total volume is...
(Solved)
A measuring cylinder contains 50cm3 of light oil at 0oC. When a lump of dried ice is placed in the oil, the total volume is 72cm3. Determine the density of the ice.
Date posted:
April 2, 2019
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Answers (1)
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The figure below shows a balloon carrying hydrogen gas 3m3 of density 0.09kgm-3. The mass of the balloon fabric is 2kg and the density of...
(Solved)
The figure below shows a balloon carrying hydrogen gas 3m3 of density 0.09kgm-3. The mass of the balloon fabric is 2kg and the density of air is 1.25kgm-3
i) Determine the tension in the string
ii) If the string is suddenly cut, calculate the acceleration of the balloon upwards
iii) What is the maximum mass of the equipment the balloon can lift at a constant velocity
Date posted:
April 2, 2019
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Answers (1)
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The graph below shows the variation between force and distance for a boy pushing a concrete block of mass 25kg through a vertically height of...
(Solved)
The graph below shows the variation between force and distance for a boy pushing a concrete block of mass 25kg through a vertically height of 12m.
(i) Determine the total work done by the boy within 70m
(ii) How much energy is wasted?
(iii) Give an account for the energy wasted
Date posted:
April 2, 2019
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Answers (1)
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Figure below shows a wire loop with a string that has been dipped into soap solution.
(Solved)
Figure below shows a wire loop with a string that has been dipped into soap solution.
i) Sketch a similar diagram to show the observed effect if the soap film is punctured at X
ii) Explain the observations made in (i) above
Date posted:
April 2, 2019
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Answers (1)
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The diagram figure below shows a steel ball bearing gently dipped in a viscous liquid contained in a tall cylinder.
(Solved)
The diagram figure below shows a steel ball bearing gently dipped in a viscous liquid contained in a tall cylinder.
Name giving their directions the forces acting on the ball bearing as it moves down the cylinder.
Date posted:
April 2, 2019
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Answers (1)
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Give one difference between limiting and dynamic forces of friction
(Solved)
Give one difference between limiting and dynamic forces of friction
Date posted:
April 2, 2019
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Answers (1)
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Explain why it is easier to ride a bicycle round a bend on a road if the surface is dry than when it is wet
(Solved)
Explain why it is easier to ride a bicycle round a bend on a road if the surface is dry than
when it is wet
Date posted:
April 2, 2019
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Answers (1)
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The figure below shows a block of mass 25g and density 200kg/m3 submerged beam by means of a thread. A mass of 2g if suspended...
(Solved)
The figure below shows a block of mass 25g and density 200kg/m3 submerged beam by means of a thread. A mass of 2g if suspended form the beam as shown in the figure below.
(i) Determine the up thrust force acting on the block.
(ii) Calculate the density of the liquid.
Date posted:
April 2, 2019
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Answers (1)
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A crane lifts a load 500kg through a vertical distance of 4m in 8 seconds. Determine:
(Solved)
A crane lifts a load 500kg through a vertical distance of 4m in 8 seconds. Determine:
(i) Work done by the crane
(ii) Power developed by the crane
(iii) Efficiency of the crane given that it is operated by an electric motor rated 2.8Kw
Date posted:
April 2, 2019
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Answers (1)
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A bicycle has wheels 66 cm in diameter. Its crank wheel has 44 teeth and the rear sprocket 16 teeth. The crank radius is 16.5...
(Solved)
A bicycle has wheels 66 cm in diameter. Its crank wheel has 44 teeth and the rear sprocket 16 teeth. The crank radius is 16.5 cm.
(i) Determine the radius of the rear sprocket.
(ii) The bicycle moves when the rear sprocket is made to move. Hence determine the
velocity ratio.
Date posted:
April 2, 2019
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Answers (1)
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A wheel and axle are used to raise a load of 280N by a force 40N applied to the rim of the
wheel. If the radii...
(Solved)
A wheel and axle are used to raise a load of 280N by a force 40N applied to the rim of the
wheel. If the radii of the rim and axle are 70cm and 5cm respectively, calculate:
(i) The mechanical advantage
(ii) The velocity ratio
(iii) The efficiency
Date posted:
April 2, 2019
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Answers (1)