C.
It is a motion with uniform acceleration, meaning that the acceleration will not change.
The object is thrown upwards with a positive velocity. This shows that the upward direction is positive. The object will decelerate due to gravity at a magnitude of 9.81 m/s2. Therefore, the acceleration is -9.81 m/s2.
Note that even though the velocity of the object is momentarily 0 m/s at maximum height, there is still a constant acceleration.
This allows the object first decelerate upwards, then change direction at max height, and finally accelerate downwards. So in this case, the acceleration is always negative and unchanged.
Hey! I know you've probably already finished the quiz already, but I just wanted to let you know the correct answer should be D. I wish I could tell you why, but I ended up getting that answer through a bit of trial and error myself... Anyway, good luck!
1) D
2) D.) Greater than 
Explanation:
1)
The phenomenon of total internal reflection occurs when a ray of light hitting the interface between two mediums is totally reflected back into the original medium, therefore no refraction into the second medium occurs.
This phenomenon occurs only if two conditions are satisfied:
- The index of refraction of the first medium is larger than the index of refraction of the 2nd medium
- The angle of incidence is greater than a certain angle called critical angle
In picture 1, we have 4 different diagrams. In the diagrams:
- The red arrow represents the incident ray
- The green arrow represents the refracted ray
- The blue arrow represents the reflected ray
Total internal reflection occurs when there is no refraction, therefore when there is no green arrow: this occurs only in figure D, so this is the correct option. (in figure C, there is a refracted ray but it is parallel to the interface: this condition occurs when the angle of incidence is exactly equal to the critical angle, however in this problem, the angle of incidence is greater than the critical angle, so the correct option is D)
2)
As we stated in problem 1), total internal reflection occurs when the angle of incidence is equal or greater than the critical angle. Therefore in this case, the angle of incidence must be
D.) Greater than 
<span>its hard to turn cooked pancakes back into batter</span>
Answer:
43.83
N
Explanation:
Given that,
The mass of an object, m = 34.4 kg
The coefficients of static and kinetic frictions for plastic on wood are 0.53 and 0.40, respectively.
The force of static friction,

The force of kinetic friction,

Net force acting on the object is :
F = 178.67-134.84
= 43.83 N
Hence, this is the required solution.