A washing machine is being redesigned to handle a greater volume of water. One part is a pipe with a radius of 3 centimeters (cm) and a length of 11cm. It gets replaced with a pipe of radius 4cm, and the same length. The new pipe can hold wπ more cubic centimeters (cm3) of water than the old pipe, where w is a constant. What is the value of w ?
Q. A washing machine is being redesigned to handle a greater volume of water. One part is a pipe with a radius of 3 centimeters (cm) and a length of 11cm. It gets replaced with a pipe of radius 4cm, and the same length. The new pipe can hold wπ more cubic centimeters (cm3) of water than the old pipe, where w is a constant. What is the value of w ?
Calculate volume of old pipe: Calculate the volume of the old pipe.The volume of a cylinder (pipe) is given by the formula V=πr2h, where r is the radius and h is the height (or length) of the cylinder.For the old pipe, r=3 cm and h=11 cm.Vold=π×(3cm)2×11cm=π×9cm2×11cm=99πcm3.
Calculate volume of new pipe: Calculate the volume of the new pipe.For the new pipe, r=4cm and h=11cm (same as the old pipe).Vnew=π×(4cm)2×11cm=π×16cm2×11cm=176πcm3.
Calculate difference in volume: Calculate the difference in volume between the new pipe and the old pipe.The difference in volume will be the volume of the new pipe minus the volume of the old pipe.Difference = Vnew−Vold=176π cm3−99π cm3=(176−99)π cm3=77π cm3.
Identify value of w: Identify the value of w from the difference in volume.The problem states that the new pipe can hold wπ more cubic centimeters of water than the old pipe.Therefore, wπ=77π cm3.To find w, we divide both sides of the equation by π.w=π77π cm3=77.
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