Answer:
f' = 3665.51 Hz
Explanation:
given,
speed of the hawk = 24.7 m/s
frequency of screech emitted by the hawk = 3400 Hz
speed of sound = 331 m/s
By Doppler's effect
f' is the frequency received by the mouse
v is the speed of the sound
v_s is the speed of the hawk
now,
f' = 1.078 x 3400
f' = 3665.51 Hz
The frequency received by the stationary mouse is equal to 3665.51 Hz
Before a person walks through burning coal, the person will make sure their feet are very wet. When they start walking on the coal, this moisture will evaporate and form a protective gas layer underneath the person's feet. You can see examples of this if you happen to drip some water on a hot stove or any very hot surface. The water will very easily glide around on top of a newly formed layer of air underneath it -- like air hockey pucks on an air hockey table. Note that when someone walks through burning coal, typically this is also done very quickly to prevent a great deal of exposure to possible harm. By walking quickly, thinking positively, and letting the water cushion you from immediate danger over a short distance, such a task is possible. You may have also heard of physics teachers demonstrating how this principle works by sticking their hand first in a bucket of water and then quickly in a bucket of boiling molten lead. In the lead, their hand is protected briefly by a layer of gas from the evaporated water (the water vapor). I'm fairly sure that there is a name for this particular layer of gas, but I'm afraid the name is beyond me at the moment. In other words, water vapor has a low heat capacity and poor thermal conduction. Very often, the coals or wood embers that are used in fire walking also have a low heat capacity. Sweat produced on the bottom of people's feet also helps form a protective water vapor. All of this together makes it possible, if moving quickly enough, to walk across hot coals without getting burned. WARNING: Do not attempt to perform any of the actions described above. You can seriously injure yourself. Answered by: Ted Pavlic, Electrical Engineering Undergrad Student, Ohio St. (citing my source)
Answer:
Tension, T = 2038.09 N
Explanation:
Given that,
Frequency of the lowest note on a grand piano, f = 27.5 Hz
Length of the string, l = 2 m
Mass of the string, m = 440 g = 0.44 kg
Length of the vibrating section of the string is, L = 1.75 m
The frequency of the vibrating string in terms of tension is given by :
T = 2038.09 N
So, the tension in the string is 2038.09 N. Hence, this is the required solution.
Answer:
Box A
Explanation:
Let mass of each wooden box =m
Density of box A=
Density of box B =
Density,
Density of inversely proportional to volume.
The volume of box with smaller density is larger than the volume of box with large density.
When the boxes are submerged under water.
Then, the buoyant force=
Where V=Volume of displace fluid.
Density of fluid
Buoyant force of box A=
Buoyant force of box B=
Force=Buoyant force
Acceleration is directly proportional to volume.
Therefore,the box with large volume has greater acceleration.
Hence, the box A has greater acceleration.
