Answer:

Explanation:
According to “Newton's second law”
“Force” is “mass” times “acceleration”, or F = m× a. This means an object with a larger mass needs a stronger force to be moved along at the same acceleration as an object with a small mass
Force = mass × acceleration

Given that,
Mass = 5.32 kg


F = 12.7N
Normal force = mg + F sinx,
“m” being the object's "mass",
“g” being the "acceleration of gravity",
“x” being the "angle of the cart"

To find normal force substitute the values in the formula,
Normal force = 5.32 × 9.8 + 12.7 × sin(-28.7)
Normal force = 52.136 + 12.7 × 0.480
Normal force = 52.136 + 6.096
Normal force = 58.232 N
<u>Acceleration of the cart</u>:




The Doppler effect is the right concept to solve this problem. The Doppler effect is understood as the change in apparent frequency of a wave produced by the relative movement of the source with respect to its observer. Mathematically it can be described as,

Here,
= Frequency of the sound from the Whistle
f = Frequency of sound heard
v = Speed of the sound in the Air
Replacing we have that





Therefore the minimum speed to know if the whistle is working is 16.33m/s
If the transformer’s primary coil has 20 times as many turns of wire in it as the secondary coil has, then the secondary coil provides a small voltage rise for the large amount of current that flows through it.
Answer: Option B
<u>Explanation:</u>
A transformer has a two types of coils, the first one is primary coils and the second one is secondary coil. A secondary coils with hardly any turns in it provides the charges going through it just limited quantities of energy.
Without a long separation over which to do chip away at the charges streaming in the loop, the transformer delivers just a little ascent in the voltage of those charges. Be that as it may, the coil can give this little voltage to ascend to a huge current without requiring an excess of power supply from the input circuit.
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