A long distance running is running the 10000 m race. He runs the first 2000 m in 5 minutes, the next 5000 m in 14 minutes and th
2 answers:
This kind of problems are solved by dividing total distance with the total time necessary for him to get from the start to the finish line. In this case, total distance is 10000m and the total time is the sum of the times that were given (which is 26 minutes, or 1560 seconds). Dividing these two numbers, the average speed is:
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Answer:
f = 5.3 Hz
Explanation:
To solve this problem, let's find the equation that describes the process, using Newton's second law
∑ F = ma
where the acceleration is
a =
B- W = m \frac{d^2 y}{dt^2 }
To solve this problem we create a change in the reference system, we place the zero at the equilibrium point
B = W
In this frame of reference, the variable y' when it is oscillating is positive and negative, therefore Newton's equation remains
B’= m
the thrust is given by the Archimedes relation
B = ρ_liquid g V_liquid
the volume is
V = π r² y'
we substitute
- ρ_liquid g π r² y’ = m \frac{d^2 y'}{dt^2 }
this differential equation has a solution of type
y = A cos (wt + Ф)
where
w² = ρ_liquid g π r² /m
angular velocity and frequency are related
w = 2π f
we substitute
4π² f² = ρ_liquid g π r² / m
f =
calculate
f =
f = 5.3 Hz