Answer: 
Explanation:
According to the conservation of linear momentum principle, the initial momentum
(before the collision) must be equal to the final momentum
(after the collision):
(1)
In addition, the initial momentum is:
(2)
Where:
is the mass of the comet
is the mass of the asteroid
is the velocity of the comet, which is positive
is the velocity of the asteroid, since it is at rest
And the final momentum is:
(3)
Where:
is the final velocity
Then :
(4)
Isolating
:
(5)

Finally:
This is the final velocity, which is also in the positive direction.
Answer: wavelength=velocity×period
Explanation:the relation between velocity, wavelength and period is
Wavelength=velocity×period
Suppose car A is moving with a velocity Va, and car b with a velocity Vb,
According the principle of conservation of momentum:
Va x Ma + Vb x Mb = (Ma + Mb) V
V = (Va x Ma + Vb x Mb)/(Ma +Mb)
V = speed of cars after coupling
V = (Va x 20 mg + Vb x 15 mg)/(20 mg + 15 mg)
Put in the values of Va and Vb, and get the V
Answer:
Explanation:19,2 or 0/4 or 5 or 40,4