They can either cancel each other or add up to a resultant force with a certain direction and modulus.
Newton's second law states that F=m*a, where F is the resultant force, ie ΣF.
Answer:
The angle of incidence is greater than the angle of refraction
Explanation:
Refraction occurs when a light wave passes through the boundary between two mediums.
When a ray of light is refracted, it changes speed and direction, according to Snell's Law:
where
:
is the index of refraction of the 1st medium
is the index of refraction of the 2nd medium
is the angle of incidence (the angle between the incident ray and the normal to the boundary)
is the angle of refraction (the angle between the refracted ray and the normal to the boundary)
In this problem, we have a ray of light passing from air into clear plastic. We have:
(index of refraction of air)
approx. (index of refraction in clear plastic)
Snell's Law can be rewritten as

And since
, we have

And so

Which means that
The angle of incidence is greater than the angle of refraction
Answer:
The half-life is 
Explanation:
Using the decay equation we have:

Where:
- λ is the decay constant
- A(0) the initial activity
- A is the activity at time t
We know the activity decrease by a factor of two in a one hour period (t = 1 h), it means that


Taking the natural logarithm on each side we have:


Now, the relationship between the decay constant λ and the half-life t(1/2) is:




I hope it helps you!