Answer:
993.52 Hz
Explanation:
The frequency of sound emitted by the stationery train is 1057 Hz.
The car travels away from the train at 20.6 m/s.
The frequency the observer hears is given by the formula:
where v = velocity of sound = 343 m/s
vo = velocity of observer
f = frequency from source
This phenomenon is known as Doppler's effect.
Therefore:
The frequency heard by the observer is 993.52 Hz.
Answer:
m = 170 g
Explanation:
Meter stick is suspended at 40 cm mark
So here the torque due to additional mass and torque due to weight of the spring must be counter balanced
given that
1) 220 g is suspended at x = 5 cm
2) 120 g is suspended at x = 90 cm
3) mass of the scale is acting at its mid point i.e. x = 50 cm
now with respect to the suspension point the torque must be balanced
so we have
by solving above equation we have
m = 170 g
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>