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A bullet moving at a velocity of 300 ms-1 hits a tree trunk of diameter 50 cm. It emerges from the opposite side with a velocity of 150 ms-1. Determine the average deceleration of the bullet in the trunk.
Date posted:
February 11, 2017
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An object dropped from a height h, attains a velocity of 6 ms-1 just before hitting the ground. Find the value of h.
Date posted:
February 11, 2017
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A pipe of radius 6 mm is connected to another pipe of radius 9 mm. If water flows in wider pipe at the speed of 2 ms-1, what is the speed in the narrower pipe?
Date posted:
February 11, 2017
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Water flows in horizontal smooth pipe. State the changes that would be observed in the nature of the flow if the speed of the water is steadily increased from low to high value.
Date posted:
February 11, 2017
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A boy standing in front of a cliff blows a whistle and hears the echo after 0.5 s. He then moves 17 metres further away from the cliff and blows the whistle again. He now hears the echo after 0.6 s. Determine the speed of the sound.
Date posted:
February 11, 2017
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A ship in an ocean sends out an ultra sound whose echo is received after 3 seconds. If the wavelength of the ultra sound in water is 7.5 cm, and the frequency of the transmitter is 20 kHz,determine the depth of the ocean.
Date posted:
February 11, 2017
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The audible frequency range for a certain person is 30 Hz and 16, 500 Hz. Determine the largest wavelength of sound in air the person can detect.
(Speed of sound in air = 330m/s)
Date posted:
February 11, 2017
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Water waves are observed as they pass a fixed point at a rate of 30 crests per minute. A particular wave crest takes 2s to travel between two fixed points 6m apart.
Determine for the wave:
i) The frequency
ii) The wavelength
Date posted:
February 11, 2017
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Calculate the wavelength of the KBC FM radio wave transmitted at a frequency of 95.6 Mega Hertz.
Date posted:
February 11, 2017
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A spring extends by 6 cm when supporting a mass of 0.06 kg on earth. When the spring is used to support the same mass on the moon, it extends by 1 cm. Determine the moon's gravitational strength. (Take gravitational field strength on earth as 10 Nkg-1)
Date posted:
February 11, 2017
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State Hooke's law.
Date posted:
February 11, 2017
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A student was supplied with a colourless liquid suspected to be water
i) Describe one chemical test that could have been used to show that the liquid was water
ii) How could it have been shown that the liquid was pure water
Date posted:
February 10, 2017
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When solid magnesium carbonate was added to a solution of hydrogen chloride in methylbenzene, there was no apparent reaction. On addition of water to the resulting mixture, there was vigorous effervescence. Explain these observations.
Date posted:
February 10, 2017
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A bee-keeper found that when stung by a bee, application of a little solution of sodium hydrogen carbonate helped to relieve the irritation from the affected area. Explain
Date posted:
February 10, 2017
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a) Give the formula of an oxide which reacts with both dilute hydrochloric acid and hot concentrated sodium hydroxide
b) Give the formulae of the products formed when the oxide in (a) above reacts with excess hot concentrated sodium hydroxide.
Date posted:
February 10, 2017
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90 cm3 of 0.01M calcium hydroxide were added to a sample of water containing 0.001 moles of calcium hydrogen carbonate
a) Write an equation for the reaction which took place
b) Calculate the number of moles of calcium ions in 90 cm3 of 0.01M calcium hydroxide.
c) What would be observed if soap solution was added dropwise to a sample of the water after the addition of calcium hydroxide? Give a reason.
Date posted:
February 10, 2017
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Write the formula of the complex ion formed in each of the reactions described below.
i) Zinc metal dissolves in hot alkaline solution
ii) Copper hydroxide dissolves in excess ammonia solution
Date posted:
February 10, 2017
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Give the name of each of the processes described below which takes place when the salts are exposed to air for sometimes
i) Anhydrous copper sulphate becomes wet
ii) Magnesium chloride forms an aqueous solution
iii) Fresh crystals of sodium carbonate, Na2CO3.10H2O become covered with white powder of formula Na2CO3.H2O
Date posted:
February 10, 2017
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Explain the following observation. A chloride dissolves in water to form an electrolyte while the same chloride dissolves in methylbenzene to form a non-electrolyte
Date posted:
February 10, 2017
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During an experiment, chlorine gas was bubbled into a solution of potassium iodide
a) State the observations made
b) Using an ionic equation, explain why the reaction is redox.
Date posted:
February 10, 2017
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State and explain what would happen if a dry red litmus paper was dropped in a gas jar dry chlorine.
Date posted:
February 10, 2017
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By using only dilute hydrochloric acid, describe how a student would distinguish between barium sulphite from barium sulphate
Date posted:
February 10, 2017
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State and explain what would happen if a dry litmus paper was dropped in a gas jar of chlorine
Date posted:
February 10, 2017
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Two reagents that can be used to prepare chlorine gas are manganese (IV) oxide and concentrated hydrochloric acid
i) Write an equation for the reaction
ii) Give the formula of another reagent that can be reacted with concentrated hydrochloric acid to produce chlorine gas
iii) Describe how the chlorine gas could be dried in the laboratory
Date posted:
February 10, 2017
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State and explain the observations made when excess ammonia gas reacts with chlorine
Date posted:
February 10, 2017
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Name the process which takes place when:
a) Solid carbon (IV) oxide (dry ice) changes directly into gas
b) A red litmus paper turns white when dropped into chlorine water.
c) Propene gas molecules are converted into a giant molecule
Date posted:
February 10, 2017
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The reaction between hot concentrated sodium hydroxide and chlorine produces sodium chlorate (V), sodium chloride and water.
a) Write the equation for the reaction
b) Give one use of sodium chlorate (V)
Date posted:
February 10, 2017
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Calcium oxide can be used to dry ammonia gas.
(a) Explain why calcium oxide is not used to dry hydrogen chloride gas
(b) Name one drying agent for hydrogen chloride gas
Date posted:
February 10, 2017
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The following two tests were carried out on chlorine water contained in two test-tubes:
a) A piece of blue flower was dropped into the first test-tube. Explain why the flower ached.
b) The second test-tube was corked and exposed to sunlight. After a few days, it was found to contain a gas that rekindled a glowing splint. Write an equation for the reaction which produced theas.
Date posted:
February 10, 2017
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State two political grievances that contributed to the Maji Maji revolt of 1905-1907 in Tanganyika
Date posted:
February 10, 2017