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$9. The kinetic energy (K.E.) of a body varies jointly as the mass " m " of the body and the square of its velocity " v ". If the kinetic energy is 4320 \mathrm{ft} / \mathrm{lb} when the mass is 45 \mathrm{lb} and the velocity is 24 \mathrm{ft} / \mathrm{sec} determine the kinetic energy of a 3000 \mathrm{lb} automobile travelling 44 \mathrm{ft} / \mathrm{sec} .$

$(iv) In a proportion a: b:: c: d b and c are called(a) means(b) extremes(c) fourth proportional(d) None of these$

$Example 1: If y varies jointly as x^{2} and z and y=6 when x=4 z=9 . Write y as a function of x and z and determine the value of y when x=-8 and z=12 .$

$10. Complete the following:(iii) If \frac{9 p q}{2 l m}=\frac{18 p}{5 m} then 5 q=$

$3. If y varies directly as x^{3} and inversely as z^{2} and t and y \doteq 16 when x=4 z=2 t=3 . Find the value of y when x=2 z=3 and t=4 .$

$4. Find the value of p if the ratios 2 p+5: 3 p+4 and 3: 4 are equal.$

$8. If y \propto \frac{1}{x} and y=4 when x=3 find x when y=24 .$