A3.0kg mass is held 4.2 m above the ground. what is the potential energy of the mass with respect to the ground?

126 joules

Potential energy is the energy possessed by a body while at rest.

It is calculated by the formula m×g×h; where m is the mass, h is the height and g is the gravitational acceleration, 10N/kg

Potential energy = m×g×h

                           = 3.0 × 4.2 × 10

                           =  126 joules

the independent variable, the one that is intentionally manipulated, is whether or not the car hits the barrier.

the dependent variable, the one that you measure the response in, is the distance that the washers travel.

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.