The large truck can rest at a stable equilibrium as compare to the small,from the definition of inertia, <span>Inertia is the tendency of an object to remain at rest or in motion.</span>
Question
What is the length of the pipe?
Answer:
(a) 0.52m
(b) f2=640 Hz and f3=960 Hz
(c) 352.9 Hz
Explanation:
For an open pipe, the velocity is given by

Making L the subject then

Where f is the frequency, L is the length, n is harmonic number, v is velocity
Substituting 1 for n, 320 Hz for f and 331 m/s for v then

(b)
The next two harmonics is given by
f2=2fi
f3=3fi
f2=3*320=640 Hz
f3=3*320=960 Hz
Alternatively,
and 

(c)
When v=367 m/s then

They will use pulleys or something with a wheel and axle
Specific gravity is the ratio between the substance's density and the density of water. Being a ratio of dimensions with same units of measure, this value is unitless.
The substance or objects sinks in water if its density is greater than that of water. On the other hand, it floats if its density is lesser compared to that of water.
Having said so, the substance or object sinks in water if the specific gravity is greater than 1 and floats if the specific gravity is lesser than 1.
sinks: SG > 1
floats: SG < 1