A machine with a velocity ratio 30,moves a load of 300N when an effort of 200N is applied. What is the efficiency of the machine?

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

The law of conservation of energy states that energy cannot be created or , energy can be from one substance to another. the first blank is ' destroyed ' and for the second blank is ' transferred '

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