A talented PHY210 student is tuning her car. She increase the engine speed from 660 rpm very (69.1 rad/s) to 4500 rpm (471 rad/s
1 answer:
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Answer:
C.
Explanation:
Apex says so
Answer:
Explanation:
The work of force 2 will be given by the vectorial equation . We know the value of
and have information about its movement, which relates to the net force
.
About this movement we can obtain the acceleration using the equation . Since it departs from rest we have
.
And then using Newton's 2dn Law we can obtain the net force F=ma, thus we will have
And we had the work done by force 2 as:
(The sign will be given algebraically since we take positive the direction to the right.)
With our values:
<em>Another (shorter but maybe less intuitive way for someone who is learning) way of doing this would have been to say that the work done by both forces would be equal to the variation of kinetic energy:</em>
<em></em>
<em>Which leads us to the previous equation straightforwardly.</em>
Answer:
7500 m
Explanation:
The radar emits an electromagnetic wave that travels towards the object and then it is reflected back to the radar.
We can call L the distance between the radar and the object; this means that the electromagnetic wave travels twice this distance, so
d = 2L
In a time of
Electromagnetic waves travel in a vacuum at the speed of light, which is equal to
Since the electromagnetic wave travels with constant speed, we can use the equation for uniform motion ,so:
(1)
where
, where L is the distance between the radar and the object
Re-arranging eq(1) and substituting, we find L: