Answer:
v = 3.00 x 10⁸ m/s
Explanation:
given,
speed of light in vacuum = 299,792,458 m/s
speed of light in scientific notation to three significant figures
v = 2.99792458 x 10⁸ m/s
by rounding off the speed to three significant figure.
v = 3.00 x 10⁸ m/s
On the fourth place the value is greater than 5 so, on the third place 1 will be added.
now, the speed with three significant figure comes out to be
v = 3.00 x 10⁸ m/s
Resistance = (voltage) / (current) =
(120 V) / (0.5 A) = <em>240 ohms</em>
If 56.5kJ are needed to raise the temp by 90°C and if the heater is 60% efficient that means that:
60% X y = 56.5kJ
where y is the electrical energy in kJ that the heater will use.
y = 94.2kJ
The same bird on the tree has more gravitational potential energy. This is because it is at a higher distance from the ground as it is on the tree, than when it is on the ground.
Considering also the formula for Gravitational Potential Energy GPE = mgh
For the bird on the ground, h =0, therefore GPE = m*9.8*0 = 0
For that on the tree = mgh = m*9.8*h
Of course the one on the tree has a value greater than zero.
Answer:
-6.49 m/s
Explanation:
This is doppler effect.
The equation is;
F_l = [(v + v_l)/(v + v_s)]F_s
Where;
F_l is frequency observed by the listener
v is speed of sound
v_l is speed of listener
v_s is speed of source of the sound
F_s is frequency of the source of the sound
In this question, the source of the sound is the moving vehicle.
Thus;
F_l = F_beat + F_s
We are given beat frequency (f_beat) as 5 Hz while source frequency (F_s) as 260 Hz.
So,
F_l = 5 + 260
F_l = 265 Hz
Since listener is sitting by car, thus; v_l = 0 m/s
Thus,from our doppler effect equation, let's make v_s the subject;
v_s = F_s[(v + v_l)/F_l] - v
Speed of sound has a value of v = 344 m/s
Thus;
v_s = 260[(344 + 0)/265] - 344
v_s = -6.49 m/s
This value is negative because the source is moving towards the listener