An object moving with constant velocity
Power is the rate at which energy is used in a circuit.
20/9.8 = 2.0 seconds. The ball stops after 2 seconds.
Answer:60 rev/min
Explanation:
Given
angular speed of first shaft 
Moment of inertia of second shaft is seven times times the rotational speed of the first i.e. If I is the moment of inertia of first wheel so moment of inertia of second is 7 I
As there is no external torque therefore angular momentum is conserved




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.