That would be reflection.
Answer:
If we use the equation for the transformation of velocities for moving frames:
v' = (v - u) / (1 - u * v / c^2) where we measure the speed of v' approaching from the left where v is in a frame moving at -u towards v'
v' = (.6 c - (-.6 c)) / (1 - (-.6 c) * .6 c / c^2) = 1.2 c / (1 + .6 * .6)
or v' = 1.2 c / (1 + .36) = .88 c
v is approaching from the left at .6 c in the reference frame and the other frame approaches from the right at -.6 c with speed u (-.6 c) and we measure the speed of v as seen in the frame moving to the left
Answer:
Potential energy is 
Explanation:
The potential energy depends on the mass, the acceleration of gravity g and the height at which the object or person is.
Potential energy 
In this case we would need to know the exact mass of the hiker in order to calculate the potential energy.
But we know the values of g and h


So, the potential energy

m is the mass of the hiker, wich is not in the description of the problem.
Answer:
True.
Explanation:
A nanometer is a unit of mass, whereas a nanosecond is a unit of time. To convert 1.3 hours to minute, you would multiply by 1 h / 60 min. Kilometer is a unit of length, whereas kilogram is a unit of mass. True.
A scientist would write that number as 1.49 x 10⁸ kilometers .
(Or, if the scientist is in France or the UK, he might write it as 1.49 x 10⁸ kilometres .)