Kinetic energy and mass are proportional.

The Kinetic energy and mass are _directly_ proportional.

Explanation:

We know that Kinetic Energy is basically termed as the capacity of a body to do work.

Kinetic energy is often used to associate with moving objects, therefore, K.E is normally termed as the energy of motion.

The formula of K.E of an object of mass and velocity is defined

K.E = 1/2mv²

From the formula, it is clear that K.E is directly proportional to its mass and also directly proportional to the square of its velocity.

For example,

If A toy plane with a mass of 10 kg is flying at 20 m/s. Its K.E will be:

K.E = 1/2mv²

      = 1/2(10)(20)²

      = 1/2(10)(400)

       = 5(400)

      = 2000 J

Now, let suppose, if we double the mass of a toy plane i.e.

m = 20 kg

so

K.E = 1/2mv²

      = 1/2(20)(20)²

      = 1/2(20)(400)

      = 10(400)

      = 400 J

Therefore, the K.E is doubled when doubled the mass.

Therefore, the Kinetic energy and mass are _directly_ proportional.