What is the definition for chemical change

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.

3. a lunar exploration vehicle was created by a research team. it weighs 3,000 kg on the earth. it needs an acceleration of 10 m/s2 on the moon. in order to have the same acceleration, what will be the net force acting on the vehicle on the earth?