<h2>
So, the correct answers are:</h2>
Travels in longitudinal waves
Travels most slowly through a gas
Speeds up when temperature is increased
Is caused by vibration
Explanation for correct answers:
Yes, it does travel in longitudinal waves
Yes, sounds weird, but travels faster in the water
Yes, does speed up when temperature is increased
And yes, Is caused by vibration.
<h2>
Wrong answer is:</h2>
Can travel through a vacuum
Explanation for wrong answer:
actually, in space, there is NO sound, because there are no particals for the sound to vibrate with, there's just empty SPACE.
Answer:
6.57 m/s
Explanation:
First use Hook's Law to determine the F the compressed spring acts on the mass. Hook's Law F=kx; F=force, k=stiffnes of spring (or spring constant), x=displacement
F=kx; F=180(.3) = 54 N
Next from Newton's second law find the acceleration of the mass.
Newton's .2nd law F=ma; a=F/m ; a=54/.75 = 72m/s²
Now use the kinematic equation for velocity (or speed)
v₂²= v₀² + 2a(x₂-x₀); v₂=final velocity; v₀=initial velocity; a=acceleration; x₂=final displacement; x₀=initial displacment.
v₀=0, since the mass is at rest before we release it
a=72 m/s² (from above)
x₀=0 as the start position already compressed
x₂=0.3m (this puts the spring back to it's natural length)
v₂²= 0 + 2(72)(0.3) = 43.2 m²/s²
v₂= = 6.57 m/s
<u>Answer</u>
1/4
<u>Explanation</u>
half life = 15 years
decay period = 30 years
The number of half-lives = 30 ÷ 15
= 2 half lives
1 ⇒(<em>after 1st half life</em>) ⇒ 1/2 ⇒ (<em>after 2nd half life</em>) ⇒ 1/4
The fraction that remained is 1/4.
force goes as 1/d^2 ... (2d)^2 => 4d^2 ...
C) decrease by a factor of four