Question

Kinetic energy varies jointly as the mass and the square of the velocity. A mass of 12 grams and velocity of 3 centimeters per second has a kinetic energy of 54 ergs. Find the kinetic energy for a mass of 2 grams and velocity of 6 centimeters per second.

Answer 1

Answer:

36 ergs

Step-by-step explanation:

Joint variation is:

If z varies jointly to x and y, then we have the expression: z = kxy, where k is a constant.

In this case, z is kinetic energy (KE), x is mass (m), and y is the square of the velocity ($v^2$). So:

KE = $kmv^2$

We have some values we can plug in to solve for k:

54 = k * 12 * $3^2$

k = 1/2

Now, we have:

$KE=\frac{1}{2} mv^2$

To find the kinetic energy for m = 2 and v = 6, we have:

KE = $\frac{1}{2} *2*6^2=36$

Thus, the kinetic energy is 36 ergs.

Hope this helps!

Answer 2

Answer:

36 ergs

Step-by-step explanation:

KE = k(mv²)

54 = k(12×3²)

k = 54/108 = ½

KE = ½mv²

KE = ½ × 2 × 6² = 36