(3) The frictional force exerted by the floor on the box
it's def. TRUE. i got the same question and i got it right
Explanation:
The compass needle moved when the wire was connected to the battery. The important point here is that the needle is affected by the wire only when both ends of the wire are connected to the battery because only at this time is current flowing through the circuit.
It would be option A (a decrease in mass with an increase in volume)
Answer:
Explanation:
Given
initially mass is stretched to 
Let k be the spring Constant of spring
Therefore Total Mechanical Energy is 
Position at which kinetic Energy is equal to Elastic Potential Energy


it is given

thus 


