Answer:
a soft foam material because soft materials absorb sound better
I think its between b or c
Answer:
3331.5 kg
Explanation:
Given:
Spring constant of the spring (k) = 24200 N/m
Frequency of oscillation (f) = 0.429 Hz
Let the mass be 'm' kg.
Now, we know that, a spring-mass system undergoes Simple Harmonic Motion (SHM). The frequency of oscillation of SHM is given as:

Rewrite the above equation in terms of 'm'. This gives,

Now, plug in the given values and solve for 'm'. This gives,

Therefore, the mass of the truck is 3331.5 kg.
Answer:
a)
n=sin i/sin r
n= -0.305/-0.428
n=0.713
b)
sin c=1/n
sin c=1/0.713
sin c= 1.403
c=sin⁻¹(1.403)
c= 40.842°
Explanation:
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