Answer:
The correct answer is option 'a' 'The momentum is always conserved while as the kinetic energy may be conserved'
Explanation:
The conservation of momentum is a basic principle in nature which is always valid in an collision between 'n' number of objects if there are no external forces on the system. It is valid for both the cases weather the collision is head on or glancing or weather the object is elastic or inelastic.
The energy is only conserved in a collision that occurs on a friction less surface and the objects are purely elastic. Since in the given question it is mentioned that only the surface is friction less and no information is provided regarding the nature of the objects weather they are elastic or not hence we cannot conclusively come to any conclusion regarding the conservation of kinetic energy as the objects may be inelastic.
Answer:
Spontaneous emission is a quantum effect, which in a semiclassical picture can be described as an emission which is stimulated by vacuum noise.
I think it's called the Aphelion
Answer:
18.36 m/s
Explanation:
We can solve this using conservation of energy. The energy in the system will be conserved since there are no outside forces acting upon it so the potential energy and kinetic energy will be equal. Giving us this formula to start:
1/2mv^2=mgh
m=mass
g=gravity
h=height
v=velocity
We can start by figuring out the total height the rock travels which we can do by subtracting the height of the frisbee by the height the rock started at.
19m-1.8m=17.2m
Now we can plug in our variables to solve for velocity.
First we negate mass since its on both sides and cancels out leaving us with.
1/2v^2=gh
Plug in.
1/2v^2=(9.8)(17.2)
1/2v^2=168.56
v^2=337.12
v=18.36m/s
