WILL GIVE BRAINIEST! Which of the following correctly defines mechanical energy?

1 energy produced by machines
2 the energy due to the motion or position of objects on a macroscopic scale
3 the difference between kinetic and potential energy of objects
4 the sum of chemical and kinetic energy of objects

Which best describes how fluids change as they travel through different portions of the convection currents? they change to solids at the outer portion of the convection currents. they change to solids at the inner portion of the convection currents. they become more dense at the outer portion of the convection currents. they become more dense at the inner portion of the convection currents

The least penetrating form of radiation is

The sound level near a noisy air conditioner is 70 db. if two such units operate side by side, the sound level near the, would bea. 70dbb. 73 dbc. 105 dbd 140 db