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
<span>Commonly when we talk about gases in science, we describe them as having the characteristics of a liquid. Imagine a rock in a bucket with liquid surrounding it. The liquid surrounds the rock and exerts pressure on it from all sides. Atmospheric pressure is much the same way. It surrounds the object and exerts pressure on it from all sides as well. Weight describes the force that gravity exerts on a mass whereas atmospheric pressure depends on the density of air at a certain point. If there were less air in our atmosphere (like Mars) the pressure would be much less and the opposite is true as well. However, the mass of a solid object would not change due to this change in air pressure and would weight the same regardless of the atmosphere.</span>
Answer:
Explanation:
Assuming there is only force in the y-component, the total net force acting on the parachute and the sky diver is:
(1)
Where:
is the drag force acting upwards
is the weight of the sky diver acting downwards, hence with negative sign
Then:
(2) This is the total net force excerted on the system parachute-sky diver, and the fact it is positive means is upwards
Now, according Newton's 2nd Law of Motion the force is directly proportional to the mass and to the acceleration of a body:
(3)
Where is the mass of the diver.
Substituting the known values and finding :
(4)
(5)
Finally:
This is the acceleration of the sky diver. Note it has a positive sign, which means its direction is upwards.
You can describe the motion of an object by its position, speed, direction, and acceleration
Then you would research the problem.
Hope this helps! :)