A karate master wants to break a board by hitting the board swiftly with his hand. The master's hand has a mass of 0.30 kg, and
1 answer:
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Answer:
The energy that the truck lose to air resistance per hour is 87.47MJ
Explanation:
To solve this exercise it is necessary to compile the concepts of kinetic energy because of the drag force given in aerodynamic bodies. According to the theory we know that the drag force is defined by
Our values are:
Replacing,
We need calculate now the energy lost through a time T, then,
But we know that d is equal to
Where
v is the velocity and t the time. However the time is given in seconds but for this problem we need the time in hours, so,
(per hour)
Therefore the energy that the truck lose to air resistance per hour is 87.47MJ
Answer:
It can be concluded that the star is moving away from the observer.
Explanation:
Spectral lines will be shifted to the blue part of the spectrum if the source of the observed light is moving toward the observer, or to the red part of the spectrum when is moving away from the observer (that is known as the Doppler effect).
The wavelength at rest for this case is 434 nm and 410 nm (,
)
Since, (444nm) is greater than
(434 nm) and
(420nm) is greater than
(410 nm), it can be concluded that the star is moving away from the observer