Negative - when the motorcycle displacement has a component in the opposite direction of the given force, that force is doing negative work on the motorcycle.
This is a Doppler effect. Generally, if you move to a frequency source, you would detect an increase in frequency and when you move away from a source you would detect a decrease.
For this question, before you pass them, you are actually approaching them, so you would hear a higher frequency than the constant 300 Hz they are playing at.
Using the condensed formula:
f ' = ((v <u>+</u> vd)/(v <u>+</u> vs)) * f
Where: vd = Velocity of the detector.
vs = Velocity of the frequency source.
v = Velocity of sound in air.
f ' = Apparent frequency.
f = Frequency of source.
v = 343 m/s, vd = detector = 27.8 m/s, vs = velocity of the source =0. (the flautists are not moving).
f = 300 Hz.
There would be an overall increase in frequency, so we maintain a plus at the numerator and a minus at the denominator.
f ' = ((v + vd)/(v - vs)) * f
f ' = ((343+ 27.8)/(343 - 0)) * 300
= (370.8/343)* 300 = 324.3
Therefore frequency before passing them = 324.3 Hz.
Cheers.
Answer: In an exothermic reaction, the products have less energy than the reactants.
Explanation: There are two types of reactions:
1. Endothermic reactions: These are the reactions in which energy is required in the reaction. The energy of the products are more than the energy of the reactants.
2. Exothermic reactions: These are the reactions in which energy is released in the reaction. The energy of the products is less than the energy of the reactants.
Hence, in an exothermic reaction, the products have less energy than the reactants.
Answer:
The magnitude of the given vector is 
Explanation:
For any given vector 
The magnitude is given by
comparing with the given vector 
we get
x = 1, y = -2, z = 3
Thus the magnitude of vector A is
Answer:
B
Explanation:
There are a pair of forces acting on the 2 interacting objects
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