Answer:True
Explanation: The mechanical waves need a medium through which to transport energy because the perturbation travels inside of the medium so it needs molecules that connect elastically the displacement of the wave. For example the sound mainly uses the air molecules to transport the energy also the sound can be traveled in solid materials like metal rods.
Answer:
Explanation:
Given:
Force, f = 5 N
Velocity, v = 5 m/s
Power, p = energy/time
Energy = mass × acceleration × distance
Poer, p = force × velocity
= 5 × 5
= 25 W.
Note 1 watt = 0.00134 horsepower
But 25 watt,
0.00134 hp/1 watt × 25 watt
= 0.0335 hp.
<span>The energy of a single photon is given by E = hc/lambda, where h is Planck's constant, c is the speed of light, and lambda is the wavelength.
Plugging the values in gives E = 6.63E-34 x 3.00E8 / 700E-9 = 2.84E-19 Joules
Now one mole of substance is equivalent to 6.02E23 particles, so one mole of these photons will be:
2.84E-19 x 6.02E23 = 1.71E5 Joules</span>
The rule to get the average speed is as follows:
average speed = average distance / average time
We are given that:
distance = 250 m
time = 110 sec
Substitute with the givens in the above equation to get the average speed as follows:
average speed = 250/110 = 25/11 meters/sec
Answer:
The right answer is:
(a) 63.83 kg
(b) 0.725 m/s
Explanation:
The given query seems to be incomplete. Below is the attachment of the full question is attached.
The given values are:
T = 3 sec
k = 280 N/m
(a)
The mass of the string will be:
⇒ ![T=2 \pi\sqrt{\frac{m}{k} }](https://tex.z-dn.net/?f=T%3D2%20%5Cpi%5Csqrt%7B%5Cfrac%7Bm%7D%7Bk%7D%20%7D)
or,
⇒ ![m=\frac{k T^2}{4 \pi^2}](https://tex.z-dn.net/?f=m%3D%5Cfrac%7Bk%20T%5E2%7D%7B4%20%5Cpi%5E2%7D)
On substituting the values, we get
⇒ ![=\frac{280\times (3)^2}{4 \pi^2}](https://tex.z-dn.net/?f=%3D%5Cfrac%7B280%5Ctimes%20%283%29%5E2%7D%7B4%20%5Cpi%5E2%7D)
⇒ ![=\frac{280\times 9}{4\times (3.14)^2}](https://tex.z-dn.net/?f=%3D%5Cfrac%7B280%5Ctimes%209%7D%7B4%5Ctimes%20%283.14%29%5E2%7D)
⇒ ![=68.83 \ kg](https://tex.z-dn.net/?f=%3D68.83%20%5C%20kg)
(b)
The speed of the string will be:
⇒ ![\frac{1}{2}k(0.4)^2=\frac{1}{2}k(0.2)^2+\frac{1}{2}mv^2](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7Dk%280.4%29%5E2%3D%5Cfrac%7B1%7D%7B2%7Dk%280.2%29%5E2%2B%5Cfrac%7B1%7D%7B2%7Dmv%5E2)
then,
⇒ ![v=\sqrt{\frac{k((0.4)^2-(0.2)^2)}{m} }](https://tex.z-dn.net/?f=v%3D%5Csqrt%7B%5Cfrac%7Bk%28%280.4%29%5E2-%280.2%29%5E2%29%7D%7Bm%7D%20%7D)
On substituting the values, we get
⇒ ![=\sqrt{\frac{280\times ((0.4)^2-(0.2)^2)}{63.83} }](https://tex.z-dn.net/?f=%3D%5Csqrt%7B%5Cfrac%7B280%5Ctimes%20%28%280.4%29%5E2-%280.2%29%5E2%29%7D%7B63.83%7D%20%7D)
⇒ ![=\sqrt{\frac{280(0.16-0.04)}{63.83} }](https://tex.z-dn.net/?f=%3D%5Csqrt%7B%5Cfrac%7B280%280.16-0.04%29%7D%7B63.83%7D%20%7D)
⇒ ![=\sqrt{\frac{280\times 0.12}{63.83} }](https://tex.z-dn.net/?f=%3D%5Csqrt%7B%5Cfrac%7B280%5Ctimes%200.12%7D%7B63.83%7D%20%7D)
⇒ ![=0.725 \ m/s](https://tex.z-dn.net/?f=%3D0.725%20%5C%20m%2Fs)