12. The answer would be C. 1.50 s. This is because if you divide 60 by 40, you will get 1.5.
13. For this one I'm not sure, but what I can tell you is that the heavier something is the faster it will sink, the lighter it is, it will float.
Answer:
In general, a scientific law is the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory.
Explanation:
Yes it is valid all the times under the consideration of acceleration due to gravity .it is not valid on space where there is no influence of gravity
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:

Answer:
The answer is 24cm
Explanation:
This problem bothers on the curved mirrors, a concave type
Given data
Object height h= 5cm
Object distance = 12cm
Focal length f=24cm
Let the image distance be v=?
Applying the formula we have
1/v +1/u= 1/f
Substituting our given data
1/v+1/12=1/24
1/v=1/24-1/12
1/v=1-2/24
1/v=-1/24
v= - 24cm
This implies that the image is on the same side as the object and it is real