Answer:
f = 214.4 Hz
Explanation:
It is a process of standing waves two waves one that travels to the right and another to the left are added, it is assumed that the frequency of the wave does not change, the result is a stable wave.
In the process of reflection of the wave there are two possibilities if the end is closed a node is formed and if it is open a belly is formed (antinode or maximum)
Let's apply these reasoning to our problem. We assume that the wave initially travels to the right, as it enters through an open end at that point it has a belly. When it reaches the other end that is open we also have a belly. As we see we have bellies at the ends, for there to be a wave inside the tube there must be a node, for the lowest resonance there is only one node, which must be in the center of the tube.
The distance from a node to a maximum (belly) corresponds to ¼ wavelength, so in this case we have within ½ tube wavelength
L = ½ λ
λ = 2L
λ = 2 0.80
λ = 1.60 m
Having the wavelength and the speed of sound let's use
v = λ f
f = v / λ
f = 343 / 1.60
f = 214.4 Hz
Important physical property:
The density of the raft must be less than 1 gram/cm .
Otherwise it won't float in water, and it'll immediately become useless.
Important chemical property:
The raft must not be soluble in water.
Otherwise is will dissolve in water, and it'll become useless
after a few minutes.
Answer:
1.28 m
Explanation:
Given;
Radius, r = 1.5 cm = 0.015 m
Time, t = 19 s
Average angular speed = 4.5 rad/s
Consider a point when the tape is moving at a constant velocity along the circumference of the circular reel of radius r. The linear velocity v at this point is given by;
v = rω ----(1)
Where
v is the linear velocity of the circular motion
r is the radius of the reel
ω is the the angular velocity.
At a point the tap undergoes a linear motion before passing round the reel of the cassette. The linear velocity v at this point is given by;
v = L/t ----(2)
where;
v is the velocity of the linear motion
L is the length of the tape (distance covered by the tape)
t is the time taken
Equating equation(1) and equation (2)
L/t = rω
L = rωt
Substituting the given values,
L = 0.015 × 4.5 × 19
L = 1.2825 m
L = 1.28 m
To find the average speed, you divide 100m by 20s,
100 / 20 = 5. You would travel 5 meters a second to travel 100 meters.