Most of the elements are metals
Given :
The focal length of a concave mirror is 18 cm.
To Find :
The radius of curvature of the concave mirror.
Solution :
We know,

Therefore, the radius of curvature of concave mirror is 36 cm.
Hence, this is the required solution.
Answer:
A) The net force
Explanation:
If two forces of equal strength act on an object in opposite directions, the forces will cancel, resulting in a net force of zero and no movement.
X=1/2 at^2
3.1=1/2 a *0.64
a=9.68
v=at
v=0.8*9.6875=7.75