Answer:

Explanation:
First of all, let's convert from nanometres to metres, keeping in mind that

So we have:

Now we can convert from metres to centimetres, keeping in mind that

So, we find:

You know that when the displacement is equal to the amplitude (A), the velocity is zero, which implies that the kinetic energy (KE) is zeero, so the total mechanical energy (ME) is the potential energy (PE).
And you know that the potential energy, PE, is [ 1/2 ] k (x^2)
Then, use x = A, to calculate the PE in the point where ME = PE.
ME = PE = [1/2] k (A)^2.
At half of the amplitude, x = A/2 => PE = [ 1/2] k (A/2)^2
=> PE = [1/4] { [1/2]k(A)^2 } = .[1/4] ME
So, if PE is 1/4 of ME, KE is 3/4 of ME.
And the answer is 3/4
For more boost and to stop chases of fire
Scalars are quantities that are fully described by a magnitude (or numerical value) alone.
Vectors are quantities that are fully described by both a magnitude and a direction.
Explanation:
F=m(v-u)/t
F=2N
m=2kg
t=2s
2=2(v-u)/2
cross multiply
2*2=2(v-u)
4=2(v-u)
4/2=v-u
v-u=2m/s
v-u is the change is velocity.