Question

Kinetic energy varies jointly as the mass and the square of the velocity. A mass of 15 grams and velocity of 3 centimeters per second has a kinetic energy of 27 ergs. Find the kinetic energy for a mass of 5 grams and velocity of 9 centimeters per second.

Answer 1

Answer:

Explanation:

Given

Kinetic energy varies jointly as mass and square of velocity

$K.E.\propto m$

$K.E.\propto v^2$

$K.E.=kmv^2$

for $m=15 gm\ and\ v=3 cm/s$

$K.E.=27 ergs$

$27=k(15)(3)^2 -----1$

for $m=5 gm, v=9 cm/s$

$K.E.=k(5)(9)^2----2$

Divide 1 & 2 we get

$\frac{27}{K.E.}=\frac{15\times 3^2}{5\times 9^2}$

$K.E.=81 ergs$