A 20 kg wagon is pulled with a force of 90 N. Ground friction provides 20 N of force in the opposite direction. What is the weight of the wagon? And why?
20 N
200 N
70 N

What is the measure of a change in an objects velocity?

When is a current produced? when the terminals of an electrochemical cell are connected by a wire if the electric circuit is opened in an electrochemical cell if the electrolyte is removed from an electrochemical cell when the electrodes are reversed in an electrochemical cell

Which is a substance that can be separated by physical means and is not the same throughout