Heat gained =Heat lost
20Lf +20x4.2 /61.5-0) = 100x4.2(90-61.5)
=340.2Jg-1
L=3.402x105Jkg-1
Wilfykil answered the question on October 1, 2019 at 07:00
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A student set-up the apparatus as shown below to determine the power of an electric heater
(Solved)
A student set-up the apparatus as shown below to determine the power of an electric heater
(i) Other than time, state the measurements that would be used to determine the quantity of heat P absorbed by ice in a unit time
(ii) Complete the circuit to show the connection of the essential circuit components
(iii) Describe how the student would proceed to determine P
(iv) Give a reason why P may not be equal to the value indicated by the manufacturer
Date posted:
October 1, 2019
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Answers (1)
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The readings tabulated below shows how the length of a helical spring varied with the load hanging on it
(Solved)
The readings tabulated below shows how the length of a helical spring varied with the load hanging on it
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Date posted:
October 1, 2019
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Answers (1)
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The diagram below shows two trolleys, A and B connected to each other by an elastic strip of negligible mass.
(Solved)
The diagram below shows two trolleys, A and B connected to each other by an elastic strip of negligible mass. The trolleys are pulled apart on a smooth plane till tension in the elastic strip is 4.0N and are then released suddenly
(a) State with reason the total momentum of the trolleys when they are just released
(b) Calculate the initial acceleration of trolley A when released
(c) The velocity of the trolley B is 0.9ms-1 just before it collides with A. Determine the velocity of A just before the collision
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Date posted:
October 1, 2019
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Answers (1)
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(Solved)
A student holds a sheet of paper at an end so that it hangs in the position A as shown below
Explain why the paper rises to the position B when the student blows air in the direction shown by the arrow
Date posted:
October 1, 2019
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Answers (1)
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The figure below shows a sheet of material with the shape of an isosceles triangle
(Solved)
The figure below shows a sheet of material with the shape of an isosceles triangle. Mark its centre of gravity accurately showing how you arrive at the answer
Date posted:
October 1, 2019
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Answers (1)
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A u-tube vertically holds two liquids L1 and L2 as shown in the figure below
(Solved)
A u-tube vertically holds two liquids L1 and L2 as shown in the figure below
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Date posted:
October 1, 2019
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Answers (1)
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The bob in the figure below is deflected then released to oscillate.
(Solved)
The bob in the figure below is deflected then released to oscillate. State and explain one factor that will determine whether the string breaks or not
Date posted:
October 1, 2019
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Answers (1)
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A single pendulum consisting of a heavy bob and string is suspended in air as shown in the figure below
(Solved)
A single pendulum consisting of a heavy bob and string is suspended in air as shown in the figure below
Mark on the diagram and name one other force acting on the bob
Date posted:
October 1, 2019
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Answers (1)
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An object weighs 2.6 N in air and 2.2 N when completely immersed in water. Determine the relative density of the object
(Solved)
An object weighs 2.6 N in air and 2.2 N when completely immersed in water. Determine the relative density of the object
Date posted:
October 1, 2019
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Answers (1)
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Complete the figure below to show how a single pulley can be arranged to a velocity ratio(V.R) of 2
(Solved)
Complete the figure below to show how a single pulley can be arranged to a velocity ratio(V.R) of 2
Date posted:
October 1, 2019
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Answers (1)
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The figure below shows a path taken by a gas molecule moving from point x to z
(Solved)
The figure below shows a path taken by a gas molecule moving from point x to z
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(b) State in full, the law of motion that governs movement from x to z
Date posted:
October 1, 2019
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Answers (1)
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The five-tick tape shown below was produced by a ticker timer connected to mains supply of 50Hz when a force pulls the trolley.
(Solved)
The five-tick tape shown below was produced by a ticker timer connected to mains supply of 50Hz when a force pulls the trolley.
Determine the acceleration of the trolley.
Date posted:
September 30, 2019
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Answers (1)
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The machine represented in the diagram can be used to lift water from a well.
(Solved)
The machine represented in the diagram can be used to lift water from a well.
A force of 50N applied on the handle lifts water of weight 180N
i) Calculate the efficiency of the machine.
ii) Give a reason why the efficiency is less than 100%.
Date posted:
September 30, 2019
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Answers (1)
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A block of metal of mass 250g at 100°C is dropped into a lagged calorimeter of heat capacity 40J/K containing 100g of water at 25°C....
(Solved)
A block of metal of mass 250g at 100°C is dropped into a lagged calorimeter of heat capacity 40J/K containing 100g of water at 25°C. The temperature of the resulting mixture was found to be 40°C. Determine; (Cw = 4200J/k)
i) Heat gained by calorimeter.
ii) Heat gained by water.
iii) Heat lost by the block.
iv) Specific heat capacity of the metal block.
Date posted:
September 30, 2019
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Answers (1)
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In an experiment, it was observed that soapy water placed on a wet smooth surface displaced the particles of non-soapy water. Sate and explain this...
(Solved)
In an experiment, it was observed that soapy water placed on a wet smooth surface displaced the particles of non-soapy water. Sate and explain this observation.
Date posted:
September 30, 2019
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Answers (1)
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Give one reason why a lift pump raises water to heights less than 10m.
(Solved)
Give one reason why a lift pump raises water to heights less than 10m.
Date posted:
September 30, 2019
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Answers (1)
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A mass of 80kg is being lifted by a force F applied on the other piston of the machine as shown in the figure...
(Solved)
A mass of 80kg is being lifted by a force F applied on the other piston of the machine as shown in the figure below.Determine the value of F needed to just lift the 80kg mass given the density of the liquid is 1.2g/cm³.
Date posted:
September 30, 2019
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Answers (1)
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The figure below shows a drop of fatty acid on a wire of diameter 1.4mm
(Solved)
The figure below shows a drop of fatty acid on a wire of diameter 1.4mm
When the drop of the fatty acid was placed on clean water surface it formed a circular patch of diameter 91cm.
i) Estimate the length of the molecule of the fatty acid.
ii) State the assumption made in part (i) above.
Date posted:
September 30, 2019
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Answers (1)
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The arrangement in the figure below was used to determine the specific heat capacity of the metal.
(Solved)
The arrangement in the figure below was used to determine the specific heat capacity of the metal.
State the precautions that need to be taken.
Date posted:
September 30, 2019
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Answers (1)
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A boy poured some boiling water into a plastic can and placed an air-tight cork on its open end. He then ran some cold water...
(Solved)
A boy poured some boiling water into a plastic can and placed an air-tight cork on its open end. He then ran some cold water on it for about 20 seconds after which he shook the can vigorously. State and explain what he observed.
Date posted:
September 30, 2019
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Answers (1)