The answer to your question would be false. It is true because duration can not lead to injury quickly.
When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted ray, and it is given by:

(2)
where

is the refractive index of the second medium and

is the refractive index of the first medium.
We can find the ratio

by using Snell's law:

(1)
where

is the angle of incidence

is the angle of refraction
By using the data of the problem and re-arranging (1), we find

and if we use eq.(2) we can now find the value of the critical angle:
Answer:
a=3.53 m/s^2
Explanation:
Vo=0 m/s (because he is not moving at the start)
V1=15 m/s
t= 4.25 s
a = (V1-Vo) / t = 15/4.25 = 3.53 m/s^2
Answer:
0.752 m/s
Explanation:
m1 = 3.00kg
u1 = 5.05m/s
m2 = 2.76kg
u2 = -3.66m/s
According to the law of conservation of momentum,
m1u1 + m2u2 = (m1+m2)v
3(5.05) + 2.76(-3.66) = (5.05+2.76)v
15.15 - 9.2736 = 7.81v
5.8764 = 7.81v
v = 5.8764/7.81
v = 0.752m/s