Why does increasing mass also increase kinetic energy and velocity?

[aatari]

Homework Statement

Hi Guys, I don't have a particular problem that I need to solve but I need help with understanding a concept. So we agree that irrespective of mass of an object they will both fall at a same rate if there is no air resistance. However, why is it then when we increase the mass of an object, the potential energy increases, which as a result increases the kinetic energy and which would also increase the velocity of that object.

Isn't this contradictory? Or am I misunderstanding something? Please help!

Homework Equations

Eg = mgh
Ek = 1/2mv^2

The Attempt at a Solution

 

[gneill]

why is it then when we increase the mass of an object, the potential energy increases, which as a result increases the kinetic energy and which would also increase the velocity of that object.

That is false. Kinetic energy is not velocity. It depends on both mass and velocity. Different mass, different KE for the same velocity.

 

[Vector1962]

For an object dropped from rest from a specific height, y = h, the total energy at h, is TE = PE + KE. At y = h, PE = mgh and KE = 0 (rest). So TE = mgh.

The value of TE calculated does not change as the object falls. At any y value along the path, the total energy is the same, this includes the point at y=0. So, at y = 0, TE = PE + KE --> mg0 + 1/2 mv² = TE = mgh. The mass cancels out which makes the velocity independent of the mass.

 

[blacksea7]

in a simple way...try imagining a bowling ball falling from 1m on your hand vs a tennis ball falling they're pulled at the same speed 9.8m/s just the mass differs the impact on your hand) that velocity is the same just if maybe your friend pushes it down while dropping it it increases the speed..