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A 1kg lump of solid wax is heated uniformly by a 100W heating element until after it has all melted. The graph below shows how...
(Solved)
A 1kg lump of solid wax is heated uniformly by a 100W heating element until after it has all melted. The graph below shows how temperature of the wax varies with time.
Explain what is happening in the sections.
(i) WX.
XY.
Use the graph to determine
(i) the specific heat capacity of wax.
(ii) the specific latent heat of fusion of the wax.
Date posted:
June 3, 2019
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Answers (1)
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A trolley of height 0.2m moving on a horizontal bench of height 3.2m strikes a barrier at the edge of the bench. The object on...
(Solved)
A trolley of height 0.2m moving on a horizontal bench of height 3.2m strikes a barrier at the edge of the bench. The object on top of the trolley flies off on impact and lands on the ground 2.5m from the edge of the bench as shown in the figure below.
Use this information to answer the questions that follow.
(i) Give a reason why the object on the trolley flies off on impact.
(ii) Determine the time taken by the object to reach the ground.
Date posted:
June 3, 2019
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Answers (1)
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The petrol air mixture in the cylinder of a car engine is ignited when the piston is in the position shown below.
Explain in terms of...
(Solved)
The petrol air mixture in the cylinder of a car engine is ignited when the piston is in the position shown below.
Explain in terms of kinetic theory why the piston moves downwards.
Date posted:
June 1, 2019
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Answers (1)
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If the mass M of object is 500g and r is 50cm. Determine the velocity of the body if the spring balance reads 81N.
(Solved)
If the mass M of object is 500g and r is 50cm. Determine the velocity of the body if the spring balance reads 81N.
Date posted:
June 1, 2019
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Answers (1)
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A stone is thrown vertically upwards from an edge of a platform. Eventually the stone lands without bouncing, on the ground below the platform. Taking...
(Solved)
A stone is thrown vertically upwards from an edge of a platform. Eventually the stone lands without bouncing, on the ground below the platform. Taking the upward velocity to be positive, sketch the velocity-time graph of the motion of the stone.
Date posted:
June 1, 2019
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Answers (1)
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The mercury column in a barometer is 760mm high. Taking the density of mercury to be 13.6g/cm³, calculate the atmospheric pressure in N/m².
(Solved)
The mercury column in a barometer is 760mm high. Taking the density of mercury to be 13.6g/cm³, calculate the atmospheric pressure in N/m².
Date posted:
June 1, 2019
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Answers (1)
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Figure below shows a non-uniform tree trunk, 9m long weighing 525N. The tree is overhanging a vertical cliff edge. A man of mass 70kg...
(Solved)
Figure below shows a non-uniform tree trunk, 9m long weighing 525N. The tree is overhanging a vertical cliff edge. A man of mass 70kg is able to walk out on the tree a distance of 1.5m from the edge of the cliff before the tree begins to topple.
Calculate the distance from the cliff edge to the centre of gravity of the tree.
Date posted:
June 1, 2019
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Answers (1)
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An object weighs 49N on earth where acceleration due to gravity is 9.8N/kg. Find the acceleration due to gravity on another planet where the same...
(Solved)
An object weighs 49N on earth where acceleration due to gravity is 9.8N/kg. Find the acceleration due to gravity on another planet where the same object weighs 40.5N.
Date posted:
June 1, 2019
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Answers (1)
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A string of negligible mass has a bucket tied at the end. The string is 60cm long and the buckets has a mass of 45g....
(Solved)
A string of negligible mass has a bucket tied at the end. The string is 60cm long and the buckets has a mass of 45g. The bucket is swung horizontally making 6 revolutions per second. Calculate:
(i) The angular velocity.
(ii) The centripetal acceleration.
(iii) The tension on the string.
(iv) The linear velocity.
Date posted:
June 1, 2019
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Answers (1)
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A block of length 50 cm, cross-sectional area of 5cm2 and density 1.4 g/cm3 is completely immersed in a liquid of density 1.08 g/cm3 find
(i)...
(Solved)
A block of length 50 cm, cross-sectional area of 5cm2 and density 1.4 g/cm3 is completely immersed in a liquid of density 1.08 g/cm3 find
(i) The mass of the block
(ii) The weight of the block in the liquid.
(iii) The apparent loss in weight of the block if three quarter of it is immersed in the liquid.
Date posted:
June 1, 2019
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Answers (1)
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An object is released to fall vertically from height of 100m. At the same time another object is projected vertically upward with velocity of 40m/s.
(i)...
(Solved)
An object is released to fall vertically from height of 100m. At the same time another object is projected vertically upward with velocity of 40m/s.
(i) Calculate the time taken before the objects meet
(ii) At what height do the objects meet?
Date posted:
June 1, 2019
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Answers (1)
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James applied a force of 400N in pushing a stationary wall. If he took one hour to push the wall, calculate the power developed.
(Solved)
James applied a force of 400N in pushing a stationary wall. If he took one hour to push the wall, calculate the power developed.
Date posted:
June 1, 2019
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Answers (1)
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A balloon filled with argon gas of volume 200 cm3 at the earth’s surface where the temperature is 200C, and the pressure 760mm of mercury....
(Solved)
A balloon filled with argon gas of volume 200 cm3 at the earth’s surface where the temperature is 200C, and the pressure 760mm of mercury. If it is allowed to ascend to a height where the temperature is 0C and the pressure 100mm of mercury, calculate the volume of the balloon.
Date posted:
June 1, 2019
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Answers (1)
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In a faulty mercury-in-glass thermometer was found that the mercury level stands at 3 cm mark in the tube at 00 C and 18 cm...
(Solved)
In a faulty mercury-in-glass thermometer was found that the mercury level stands at 3 cm mark in the tube at 00 C and 18 cm when in steam above boiling water at normal atmospheric pressure. Calculate the temperature when the mercury stands at 12 cm mark.
Date posted:
June 1, 2019
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Answers (1)
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A vernier caliper which had an error of 0.02cm was used to measure the diameter of a spherical marble. If the actual diameter was 3.67cm,...
(Solved)
A vernier caliper which had an error of 0.02cm was used to measure the diameter of a spherical marble. If the actual diameter was 3.67cm, draw a vernier caliper scale showing its reading
Date posted:
June 1, 2019
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Answers (1)
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State the name of the instrument used to take the following readings;
(i) 0.035m
(ii) 0.00245m
(Solved)
State the name of the instrument used to take the following readings;
(i) 0.035m
(ii) 0.00245m
Date posted:
June 1, 2019
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Answers (1)
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The refractive indices of water and glass are 3/2 and 4/3 respectively. Find the value of theta in the figure below.
(Solved)
The refractive indices of water and glass are 3/2 and 4/3 respectively. Find the value of theta in the figure below.
Date posted:
June 1, 2019
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Answers (1)
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The speed of green light in a prism is 1.94 x 108m/s.
(i) Determine the refractive index of the prism material. (Speed of light in air...
(Solved)
The speed of green light in a prism is 1.94 x 108m/s.
(i) Determine the refractive index of the prism material. (Speed of light in air = 3.0 x 108m/s).
(ii) Determine the critical angle of the prism material.
Date posted:
June 1, 2019
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Answers (1)
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A coin is placed beneath a transparent block of thickness 10cm and refractive index 1.56. Calculate the vertical displacement of the coin.
(Solved)
A coin is placed beneath a transparent block of thickness 10cm and refractive index 1.56. Calculate the vertical displacement of the coin.
Date posted:
June 1, 2019
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Answers (1)
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54kg of water in a metallic cylinder of heat capacity 9000JK¯¹ is heated from 10°C to 80°C using an immersion heater rated 1800W, 240V. Assuming...
(Solved)
54kg of water in a metallic cylinder of heat capacity 9000JKˉ¹ is heated from 10°C to 80°C using an immersion heater rated 1800W, 240V. Assuming that no heat is lost to the surrounding and the immersion heater works at its correct
voltage. Find.
i) The current flowing through the water.
ii) The cost of heating the same mass of water from 10°C to 80°C, every day for 30 days, if electricity cost sh.6.70 per unit.
Date posted:
May 31, 2019
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Answers (1)