v = speed of the source of sound or the train towards the listener or switchman = 40 m/s
V = actual speed of sound = 340 m/s
f = actual frequency of sound as emitted from source or the train = 1000 Hz
f' = frequency as observed by the listener or by switchman = ?
Using Doppler's law , frequency observed by a listener from a source moving towards it is given as
f' = V f /(V - v)
inserting the values
f' = 340 x 1000 /(340 - 40)
f' = 340 x 1000/300
Answer:
The answer is B: to Amplify the sound
Answer:
b
Explanation:
the ability for gases to compress is extremely helpful it allows tanks of oxygen to hold enough air for up to two hours and the strange thing about compression is that it allows some liquids to stay liquid at their boiling point allowing liquid nitrogen to stay liquid at room temperature
The answer to question one is A.
The answer to question two is A.
The answer to question three is D.
Answer:
The forces creating the net force must lie in the same direction.
Explanation:
newton's second law states that the net force acting on the body is equal to the product of mass and the acceleration of the body.
If there are several forces acting on the body in different directions, then we have to find teh net force by using the vector sum and then find the acceleration.
It is not necessary that all the forces acting in the same direction.
if they are in different directions then we have to find the net force by t=using the formula for the vector sum.
