Answer:
(a). The spring compressed is
.
(b). The acceleration is 1.5 g.
Explanation:
Given that,
Acceleration = a
mass = m
spring constant = k
(a). We need to calculate the spring compressed
Using balance equation

....(I)
The spring compressed is
.
(b). If the compression is 2.5 times larger than it is when the mass sits in a still elevator,
The compression is given by

Here, acceleration is zero
So, 
We need to calculate the acceleration
Put the value of x in equation (I)




Hence, (a). The spring compressed is
.
(b). The acceleration is 1.5 g.
Explanation:
Since the balloon is not accelerating means that the net force on the balloon is zero. This implies that the weight of balloon must be equal to the buoyant force on balloon.
Hence, the buoyant force equals the weight of air displaced by the balloon, also 20,000 N.
Weight of the air displaced = density of air × volume
The density of air at 1 atm pressure and 20º C is 1.2 kg/m³
the volume V = 20,000/(1.2×9.8) = 1700 m³
Explanation:
Lasers produce a narrow beam of light in which all of the light waves have very similar wavelengths. The laser's light waves travel together with their peaks all lined up, or in phase. This is why laser beams are very narrow, very bright, and can be focused into a very tiny spot.
Answer:
f3 = 102 Hz
Explanation:
To find the frequency of the sound produced by the pipe you use the following formula:

n: number of the harmonic = 3
vs: speed of sound = 340 m/s
L: length of the pipe = 2.5 m
You replace the values of n, L and vs in order to calculate the frequency:

hence, the frequency of the third overtone is 102 Hz
Ofcoure the elephante as the elephant has more weight