Answer:
Velocity, v = 0.239 m/s
Explanation:
Given that,
The distance between two consecutive nodes of a standing wave is 20.9 cm = 0.209 m
The hand generating the pulses moves up and down through a complete cycle 2.57 times every 4.47 s.
For a standing wave, the distance between two consecutive nodes is equal to half of the wavelength.

Frequency is number of cycles per unit time.

Now we can find the velocity of the wave.
Velocity = frequency × wavelength
v = 0.574 × 0.418
v = 0.239 m/s
So, the velocity of the wave is 0.239 m/s.
Speed of the car given initially
v = 18 m/s
deceleration of the car after applying brakes will be
a = 3.35 m/s^2
Reaction time of the driver = 0.200 s
Now when he see the red light distance covered by the till he start pressing the brakes


Now after applying brakes the distance covered by the car before it stops is given by kinematics equation

here
vi = 18 m/s
vf = 0
a = - 3.35
so now we will have


So total distance after which car will stop is


So car will not stop before the intersection as it is at distance 20 m
More force is needed for more mass. Therefore, if the mass is greater and the force is not enough then the object will less likely accelerate
<span>The loudness of the sound increases gradually as the air is slowly introduced in to the jar. This is because sound needs a physical medium and in a vacuum there is none. The air provides that medium and as it is introduced, the transfer of sound energy increases</span>
Dinosaurs but I need the whole groups yo tell you ;)