Answer: If the woodpecker drums upon a tree 5 times in one second, then the frequency is 5 Hz; each drum must endure for one-fifth a second, so the period is 0.2 s.
For the position of button we can use force balance as
Friction Force = Centripetal force
so here we will have

here we know that
R = radius of circle where button is placed

f = 35 rev/min


now from above equation


so friction coefficient will be 0.33
Answer:
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Explanation:
= Mass of the Earth = 5.98 × 10²⁴ kg
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
= Distance from the center of the Moon to the center of Earth = 6371000 m
= Distance from the center of the earth center to sun center
= Mass of moon = 
M = Mass of sun = 



Hence the force of moon on earth is 0.00566 times the force of earth on moon center to center
The most effective way to prevent beach erosion is to replant mangrove trees, seaweeds and seagrass. The strategic planting of vegetation can be used to help control erosion. The roots of these plants help to anchor the sand and ensure that it is not carried off in erosion. This is why many areas plant seagrass and build marshes along coasts to prevent erosion.