Answer:
Fractional error = 0.17
Percent error = 17%
F = 112 ± 19 N
Explanation:
Plug in the values to find the force:
F = (3.5 kg) (20 m/s)² / (12.5 m) = 112 N
Find the fractional error:
ΔF/F = Δm/m + 2Δv/v + Δr/r
ΔF/F = 0.1/3.5 + 2(1/20) + 0.5/12.5
ΔF/F = 0.17
Multiply by 100% to find the percent error:
ΔF/F × 100% = 17%
Solve for the absolute error:
ΔF = 0.17 × 112 N = 19 N
Therefore, the force is:
F = 112 ± 19 N
Answer:
a

b

Explanation:
From the question we are told that
The mass of the rock is 
The length of the small object from the rock is 
The length of the small object from the branch 
An image representing this lever set-up is shown on the first uploaded image
Here the small object acts as a fulcrum
The force exerted by the weight of the rock is mathematically evaluated as

substituting values


So at equilibrium the sum of the moment about the fulcrum is mathematically represented as

Here
is very small so
and 
Hence

=> 
substituting values


The mechanical advantage is mathematically evaluated as

substituting values


Individuals have different traits because they are not twins so they should not be alike also because people have different genes witch would give them different traits. For example not every individual has blonde hair and blue eyes because they did not inherit those traits.