Roberto has twice the mass his sister Mary has but runs at the same velocity as Mary. Will his kinetic energy be twice as much? Show your work.

Yes, Roberto will have twice the kinetic energy

Explanation:

The equation for kinetic energy is Ke = 1/2(m)v^2

The variable m is not squared by anything, which means it is directly proportional to the equation. If you were to multiply m by 2, it would in turn multiply the entire equation by 2, getting you an outcome with twice as much kinetic energy.

layers of the earth affect the waves and these effects are seen on instruiments such as seimometers

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.