Answer:
(a) P = 459.055 N.
(b) the refrigerator tips.
Explanation:
Given, the angle of ramp is 20°.
When the weight of refrigerator is resolved in directions parallel and perpendicular to ramp, 75×g×sin(20°) and 75×g×cos(20°).
⇒ normal contact force is 75×g×cos(20°).
⇒ frictional force is 0.3×75×g×cos(20°) = 207.414 N
so, total opposite force is 207.414 + 75×g×sin(20°) = 459.055 N.
so, the force needed is P = 459.055 N
And as the moment due to both opposite force and P force are in same direction the refrigerator tips rather than just sliding.
Answer:
Regular reflection
Explanation:
- Reflection is the phenomenon that occurs when a light wave hits the interface between two different mediums and it bounces off back into the same medium. The angle of reflection (measured between the reflected ray and the perpendicular to the interface) is equal to the angle of incidence (measured between the incident ray and the perpendicular to the interface).
There are two different types of reflection:
- Regular reflection: this occurs when the interface between the two mediums is smooth (such as in the case of the still lake), so all the parallel light waves (which have same angle of incidence) are reflected exactly with the same angle of reflection (so, they come out all with same direction)
- Diffuse reflection: this occurs when the interface between the two mediums is not smooth, so each light ray is reflected with a different angle because it hits the interface with a different angle of incidence.
Therefore, in the case of the still lake, the correct answer is regular reflection.
The answer is B. the germinal stage