52m/s is the answer because before it was gonna accelerate it was 52 m/s
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
Answer: C. Some of uranium's mass is converted into energy, so the smaller atoms have less mass.
Explanation:
From Einstein's mass-energy relation:
E = mc²
Mass and energy are equivalent. Mass can be converted into energy and energy into mass.
When Uranium atoms under go nuclear fission, smaller atoms are formed and huge amount of energy is released. This energy comes from the mass difference of the uranium nuclei and new nuclei formed. This mass converted into energy according to Einstein's equation.
All except C, feelings are not physical.
Answer:
a) the total circle of "initial" is Epot./Eel. and the total circle of "final" is Ekin.
b)intia: 0.5 * 50 * 4^2 = 400 J
final: 0 J = 0.5 * 50 * 0^2
Explanation:
c) in the initial phase the spring is compressed and so has Epot but then the Energie changes to be totally Ekin (in final phase) and so the Epot becomes 0
