Here we can use momentum conservation as in this type of collision there is no external force on it

now here we can say




now here we can say


now by coefficient of restitution
for elastic collision we know that e = 1


now by solving the two equation


also we know that

so final speed of the nail is 6.875 m/s
C. Negative force. The dog isn't going to learn that way.
Answer:
No
Explanation:
You can easily injury yourself due to the force of gravity.
Answer:
as the period decreases, the frequency and energy of the wave increase
Explanation:
Electromagnetic waves are oscillations of the electric and magnetic fields, described by maxwell's equations, the speed of the wave is called the speed of light
c = λ f
E = E cos (kx - wt)
Angular velocity is related to frequency and period.
w = 2π f = 2π / T
Let's analyze what happens when the wave period decreases, angular velocity and frequency increase.
This increase in frequency is reflected with the Planck equation in wave energy
E = h f
Therefore the wave carries more energy and can lead to stronger interactions with matter.
In summary, as the period decreases, the frequency and energy of the wave increase