Answer:
elative magnitude of the two forces is the same and they are applied in a constant direction.
Explanation:
Newton's second law states that the sum of the forces is equal to the mass times the acceleration
∑ F = m a
in this case there are two forces on the x axis
F_applied - fr = 0
since they indicate that the velocity is constant, consequently
F_applied = fr
the relative magnitude of the two forces is the same and they are applied in a constant direction.
a)
, 
The work done by the student in each trial is equal to the gravitational potential energy gained by the student:

where
m = 68 kg is the mass of the student
g = 9.8 m/s^2 is the acceleration of gravity
is the gain in height of the student
For the first student,
, so the work done is

The second student runs up to the same height (3.5 m), so the work done by the second student is the same:

2)
, 
The power exerted by each student is given by

where
W is the work done
t is the time taken
For the first student,
and
, so the power exerted is

For the second student,
and
, so the power exerted is

I guess the problem is asking for the induced emf in the coil.
Faraday-Neumann-Lenz states that the induced emf in a coil is given by:

where
N is the number of turns in the coil

is the variation of magnetic flux through the coil

is the time interval
The coil is initially perpendicular to the Earth's magnetic field, so the initial flux through it is given by the product between the magnetic field strength and the area of the coil:

At the end of the time interval, the coil is parallel to the field, so the final flux is zero:

Therefore, we can calculate now the induced emf by using the first formula:
Correct answer is letter B. sandstone