Albert Einstein, in his theory of special relativity, determined that the laws of physics are the same for all non-accelerating observers, and he showed that the speed of light within a vacuum is the same no matter the speed at which an observer travels
Answer:
The angle of incidence is the angle formed by the incident ray and the perpendicular to the surface. Together, the angle of incidence and the angle the incident ray makes with the surface form a right angle (90 degrees). The angle of incidence is therefore given by the following expression:
Angle of incidence = 90 degrees - angle ray makes with the surface
In your example
Angle of incidence = 90 degrees - 40 degrees = 50 degrees
The law of reflection states that the angle of incidence equals the angle of reflection, which is also measured with respect to the perpendicular to the surface, so
Angle of reflection = Angle of incidence = 50 degrees.
The person's horizontal position is given by
and the time it takes for him to travel 56.6 m is
so your first computed time is the correct one.
The question requires a bit of careful reading, and I think there may be a mistake in the problem. The person's vertical velocity at time is
which tells us that he would reach the ground at about . In this time, he would have traveled
But we're told that he is caught by a net at 56.6 m, which would mean that the net cannot have been placed at the same height from which he was launched. However, it's possible that the moment at which he was launched doesn't refer to the moment the cannon went off, but rather the moment at which the person left the muzzle of the cannon a fraction of a second after the cannon was set off. After this time, the person's initial vertical velocity would have been a bit smaller than .
Using the conversion factor:
1 atm = 101.3 kPa
7.83 / 101.3
= 0.077 atm