Answer: (d)
Explanation:
Given
Mass of object 
Speed of object 
Mass of object at rest 
Suppose after collision, speed is v
conserving momentum

Initial kinetic energy

Final kinetic energy

So, it is clear there is decrease in kinetic energy . Thus, energy decreases and velocity becomes 2 m/s.
Answer:
C
Explanation:
Generally, the speed of light slows down when passing through a medium that is not a vacuum. This is not always the case, but I will be ignoring the rare/exotic exceptions. Light has a harder time traveling through solids and liquids than it does with gases.
Answer:
1) The matter absorbs or reflects the light
2) Lens
3) <u><em>Concave</em></u>- curves inwards. Diverges light
b.<u><em>Convex</em></u>- curves outward. Converges light
4) The image is real if the distance of the object from the lens is greater than the focal length and virtual if it is less than the focal length
5) Lens and, for convex lenses, on the distance between the lens and the object.
6) Index of refraction?
Explanation:
I hope this helped you, sorry if anything is wrong
Answer:

Explanation:
given,
side slope = 1 : 1
hydraulic depth(y) = 5 ft
bottom width (b)= 8 ft
x = 1
Q = 2,312 ft³/s
n = 0.013
slope of channel = ?



R = 4.69 m
using manning's equation



S = 0.406
