The student who displaced the spring by 2 cm has less potential energy than the student who displaced the spring by 4 cm, this is because potential energy (elastic) is directly proportionate to extension (displaced amount), so as the amount of displacement of the spring is higher, then the potential energy of the springs is higher and vice versa.
I would use a resistor rated for 1 W or more. Not less.
This group is called “noble gases” because they do not react with other elements. This is because they have a full valence shell.
Answer:
At an angle of 
Explanation:
Assume the river flows from East to West so for the swimmer to cross across it, assume he crosses it from West to East.
The resultant speed will be given by
