Answer:
A plane mirror is a mirror with a flat (planar) reflective surface. For light rays striking a plane mirror, the angle of reflection equals the angle of incidence. The angle of the incidence is the angle between the incident ray and the surface normal (an imaginary line perpendicular to the surface).
The formula for getting the distance will be distance = speed x time
D = S x T
speed or velocity = 50km/h
time = 0.5 h
the equation will be done directly because it's already in it's SI units
distance = 50km/h x 0.5h
hour cancels hour and the equation remains = 50km x 0.5
Ans = 25 km
the train will move 25 km far in 0.5h
Answer:

Explanation:
The potential energy associated with a body (m) located at a given height (h) above a reference point is defined as:

At the reference point the potential energy is zero. In this case the body is below the reference point (the ceiling), therefore, the value of h is negative:

Answer:
The restoring force is directly proportional to the displacement of the block.
Explanation:
For a spring-mass system, the restoring force is given by Hooke's Law:
F = -kx
where
F is the restoring force
k is the spring constant
x is the displacement of the block, attached to the end of the spring
As we see from the equation, the restoring force is directly proportional to the displacement of the block. So, the correct answer is
The restoring force is directly proportional to the displacement of the block.
Answer:
See attachment for step by step answer and explanation.
Explanation: