The net force is (40 Newtons) (down the road).
But 40 Newtons is not going to move a piano very enthusiastically.
A Headland,a Sea Cave,a Sea Arch, and a sea cut cliff.
Answer:

Explanation:
As we know that sound level is given as

so here we have

now we can take anti log both sides

so we have

so above is the expression for the intensity of sound in terms of reference intensity and sound level
Answer:
At focus
Explanation:
A concave mirror is converging in nature. In a mirror, concave in nature, the rays which are parallel to the principal axis are supposed to be coming from very large distances or we assume the source to be placed at infinity for such rays which are parallel to the principal axis.
These rays, parallel to the principal axis, coming from infinity, converges at the focus of the mirror concave in nature after reflecting from the concave mirror
Answer:
B. an action-reaction force pair