Wow ! This will take more than one step, and we'll need to be careful
not to trip over our shoe laces while we're stepping through the problem.
The centripetal acceleration of any object moving in a circle is
(speed-squared) / (radius of the circle) .
Notice that we won't need to use the mass of the train.
We know the radius of the track. We don't know the trains speed yet,
but we do have enough information to figure it out. That's what we
need to do first.
Speed = (distance traveled) / (time to travel the distance).
Distance = 10 laps of the track. Well how far is that ? ? ?
1 lap = circumference of the track = (2π) x (radius) = 2.4π meters
10 laps = 24π meters.
Time = 1 minute 20 seconds = 80 seconds
The trains speed is (distance) / (time)
= (24π meters) / (80 seconds)
= 0.3 π meters/second .
NOW ... finally, we're ready to find the centripetal acceleration.
<span> (speed)² / (radius)
= (0.3π m/s)² / (1.2 meters)
= (0.09π m²/s²) / (1.2 meters)
= (0.09π / 1.2) m/s²
= 0.236 m/s² . (rounded)
If there's another part of the problem that wants you to find
the centripetal FORCE ...
Well, Force = (mass) · (acceleration) .
We know the mass, and we ( I ) just figured out the acceleration,
so you'll have no trouble calculating the centripetal force. </span>
Use the concept of beat frequency to find the applicable final freqeuncy for 20Hz beat frequency.
Beat can be defined as 'the interference pattern between two sounds of slightly different frequencies0
The expression for beat frequency is given as
![f_{beat} = |f_1-f_2|](https://tex.z-dn.net/?f=f_%7Bbeat%7D%20%3D%20%7Cf_1-f_2%7C)
Where,
Final frequency
Initial frequency
The beat frequency for us is 25Hz and the initial frequency is 240Hz, then
![20= |f_2-240|](https://tex.z-dn.net/?f=20%3D%20%7Cf_2-240%7C)
Being an absolute value, two values are possible, both in addition and subtraction:
![f_2 = 240 \pm 20](https://tex.z-dn.net/?f=f_2%20%3D%20240%20%5Cpm%2020)
The two possible values are
![f_2 = 220Hz](https://tex.z-dn.net/?f=f_2%20%3D%20220Hz)
![f_2 = 260Hz](https://tex.z-dn.net/?f=f_2%20%3D%20260Hz)
Answer: Acted on by equal forces in opposite direction
Explanation:
Newton's First Law says that every body continue in its state of rest or constant speed on a straight line unless being acted upon by an external force.
Answer:
<em>113.4 J</em>
Explanation:
<u>Elastic Potential Energy</u>
Is the energy stored in an elastic material like a spring of constant k, in which case the energy is proportional to the square of the change of length Δx and the constant k.
![\displaystyle PE = \frac{1}{2}k(\Delta x)^2](https://tex.z-dn.net/?f=%5Cdisplaystyle%20PE%20%3D%20%5Cfrac%7B1%7D%7B2%7Dk%28%5CDelta%20x%29%5E2)
The spring has a natural length of 0.7 m and a spring constant of k=70 N/m. When the spring is stretched to a length of 2.5 m, the change of length is
Δx = 2.5 m - 0.7 m = 1.8 m
The energy stored in the spring is:
![\displaystyle PE = \frac{1}{2}70(1.8)^2](https://tex.z-dn.net/?f=%5Cdisplaystyle%20PE%20%3D%20%5Cfrac%7B1%7D%7B2%7D70%281.8%29%5E2)
PE = 113.4 J
Answer:
If a coil of wire is placed in a changing magnetic field, a current will be induced in the wire. This current flows because something is producing an electric field that forces the charges around the wire. (It cannot be the magnetic force since the charges are not initially moving). ... that determines the induced current.