The fraction of energy that is lost is 25%, it depends how fast the ball was going until it lost 25% of its energy, the gravitational energy was transferred into the kinetic energy that helped the ball bounce back
Since momentum is a vector quantity, take any direction as positive and other as negative. Answer won't change.
Answer:

Explanation:
F = Magnetic force = 4.11 N
= Net current
= Current in one of the wires = 7.68 A
B = Magnetic field = 0.59 T
= Angle between current and magnetic field = 
= Length of wires = 2.64 m
= Current in the other wire
Magnetic force is given by

Net current is given by

The current I is
.
Before coming into conclusion first we have to understand both scalar and vector .
A scalar quantity is a physical quantity which has only magnitude for it's complete specification.
A vector quantity is that physical quantity which not only requires magnitude but also possesses direction for it's complete specification.
So the most important factor that differentiate vector from scalar is the direction.
As per the question the student is doing an experiment where he is recording the data obtained during the process.
In order to arrange them in data table, he should ask about the direction of the quantity under consideration.
Hence the correct option is the third option(C)i.e does the measurement include direction?