It should be A.
A ball bouncing is moving so if it’s moving that means it has kinetic energy. It also has potential energy because when it hits the floor it kind of stops so it has potential.
-Hope this helps.
W=mgh
W=(6)(9.8)(4)
W= 235.2J
Near the surface of reflection, reflected wave may interfere with incident wave leading to production of constructive and as well as destructive interference. This in turn, can result to resonance as well as enhancement of the sound intensity as the waves of reflection adds to incident wave. Therefore, the girl would higher intensity of reflected waves as compared to incident waves.
Therefore, statement A is correct.
Answer:

Explanation:
Given that,
Mass of the object, m = 100 grams
Volume of the object, V = 20 cm³
We need to find the density of the object. We know that, density is equal to mass per unit volume. So,

So, the density of the object is equal to
.
Answer:
11.27N
Explanation:
Given parameters:
Mass of the book = 1.15kg
Unknown:
Magnitude of the normal force = ?
Solution:
The normal force is the vertical force exerted by a body on an object.
It can be described as the weight of an object.
Normal force = mass x acceleration due to gravity
Normal force = 1.15 x 9.8 = 11.27N