From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is

Here,
f = Focal Length
R = Radius
Rearranging to find the radius we have,

Replacing with our values,
R = 2(13.8cm)
R = 27.6cm
Therefore the radius of the spherical surface from which the mirror was made is 27.6cm
A- hypothesis
You usually write hypothesis in science it’s something that can usually be tested.
B- prediction
Made before you do an science experiment, they’re usually like what you think could happen or will happen.
C- theory
Theses aren’t used with scientific evidence, they’re usually things that people believe happened. Example: Some believe Big Foot is real. But no one will ever know because its a theory
D- is already been eliminated, not all are right.
Answer is A
Hope this helped :)
Answer:
A non-contact force is a force which acts on an object without coming physically in contact with it.
Explanation:
For example:
<em>Gravitational force.</em>
<em>Magnetic force.</em>
<em>Electrostatics.</em>
<em>Nuclear force.</em>
It should be answer choice b
The power required is 1.6 kW.
Answer:
Explanation:
Power is defined as the amount of work done on any object for a given time interval. In other words, power is the amount of force required to move an object in a given period of time.
Power = Work done / time taken for that work done.
Here the force is given as 800 N and the displacement is given as 2.5 m, while the time required for the displacement is given as 1.22 seconds.
So the power will be ratio of the product of force acting on the weightlifter, displacement of the weight to the time taken for that displacement.
Power = (800×2.5)/1.22 =1639 W
So the power required is 1.6 kW.