Answer:
It remains the same.
Explanation:
During physical change, the mass, number of atoms and number of molecules will remain the same.
Answer:
3100 m/s
Explanation:
The relationship between frequency and wavelength of a wave is given by the wave equation:

where
v is the speed of the wave
f is its frequency
is the wavelength
For the wave in this problem,
f = 15,500 Hz

Therefore, the wave speed is

Answer:
6.5e-4 m
Explanation:
We need to solve this question using law of conservation of energy
Energy at the bottom of the incline= energy at the point where the block will stop
Therefore, Energy at the bottom of the incline consists of the potential energy stored in spring and gravitational potential energy=
Energy at the point where the block will stop consists of only gravitational potential energy=
Hence from Energy at the bottom of the incline= energy at the point where the block will stop
⇒
⇒
Also 
where
is the mass of block
is acceleration due to gravity=9.8 m/s
is the difference in height between two positions
⇒
Given m=2100kg
k=22N/cm=2200N/m
x=11cm=0.11 m
∴
⇒
⇒
⇒h=0.0006467m=
its C because i just anwserd it & it was right