A dog whistle is designed to produce a sound with a frequency beyond that which can be heard by humans (between 20,000 Hz and 27
1 answer:
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Explanation:
a)
where is the distance of the mass
from the axis of rotation. When the axis of rotation is placed at the end of the rod, the moment of inertia is due only to one mass. Therefore,
b) When the axis of rotation is placed on the center of the rod, the moment is due to both masses and the radius r is 1.5 m. Therefore,
Answer:
a) vboat = 5.95 m/s b) vriver= 1.05 m/s
Explanation:
a) As observed from the shore, the speed of the boats can be expressed as the vector sum, of the boat speed relative to the water and the river speed relative to the shore, as follows:
vb₁s = vb₁w + vrs
In one case, the boat is moving in the same direction as the water:
vb₁s = vb₁w + vrs = 7.0 m/s (1)
For the other boat, it is clear that is moving in an opposite direction:
vb₂s = vb₂w - vrs = 4.9 m/s (2)
As we know that vb₁w = vb₂w, adding both sides, we can remove the river speed from the equation, as follows:
vb₁w = vb₂w =
b) Replacing this value in (1) and solving for vriver, we have:
vriver = 7.0 m/s - 5.95 m/s = 1.05 m/s
(we could have arrived to the same result subtracting both sides in (1), and (2))