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.
Answer:
Explanation:
A ) angular velocity ω = 2π / T
= 2 x 3.14 / 60
= .10467 rad / s
linear velocity v = ω R
= .10467 x 50
= 5.23 m / s
centripetal force = m v² / R
= mg v² / gR
= 834 x 5.23² / 9.8 x 50
= 46.55 N
B )
apparent weight
= mg - centripetal force
= 834 - 46.55
= 787.45 N
C ) apparent weight
= mg + centripetal force
= 834 + 46.55
= 880.55 N.
D )
For apparent weight to be zero
centripetal force = mg
mg = mv² / R
v² = gR
= 9.8 x 50
= 490
v = 22.13 m /s
time period of revolution
= 2π R /v
2 x 3.14 x 50 / 22.13
= 14.19 s
Answer:
The external force leads to an increase on gravitational and spring potential energies.
Explanation:
The system consists of a mass, resort and Earth. According to the Principle of Energy Conservation there is a potential energy as a consequence of the interaction between Earth and the mass and spring potential energy because of the spring deformation and, besides, the existence of work due to an external force:
![F\cdot \Delta r = G\cdot m \cdot M \cdot \left(\frac{1}{r_{o}-\Delta r}-\frac{1}{r_{o}} \right)+\frac{1}{2}\cdot k \cdot [(x_{o}+\Delta r)^{2} -x_{o}^{2}]](https://tex.z-dn.net/?f=F%5Ccdot%20%5CDelta%20r%20%3D%20G%5Ccdot%20m%20%5Ccdot%20M%20%5Ccdot%20%5Cleft%28%5Cfrac%7B1%7D%7Br_%7Bo%7D-%5CDelta%20r%7D-%5Cfrac%7B1%7D%7Br_%7Bo%7D%7D%20%20%20%5Cright%29%2B%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20k%20%5Ccdot%20%5B%28x_%7Bo%7D%2B%5CDelta%20r%29%5E%7B2%7D%20-x_%7Bo%7D%5E%7B2%7D%5D)
The external force leads to an increase on gravitational and spring potential energies.
Electromagnetic and Gravitational forces are most alike because their range is not limited.
Electromagnetic waves ARE radiation.
A wave always carries energy.
