Answer:
<u><em>A. wavelength</em></u>
Explanation:
The others are about sound and how high it is. That has nothing to do with time.
Answer:
V=15.3 m/s
Explanation:
To solve this problem, we have to use the energy conservation theorem:

the elastic potencial energy is given by:

The work is defined as:

this work is negative because is opposite to the movement.
The gravitational potencial energy at 2.5 m aboves is given by:

the gravitational potential energy at the ground and the kinetic energy at the begining are 0.

An echo
Refraction
Diffraction
Transmission
reflection
Answer:
the acceleration of the car is -4.9m/s2.
the direction is opposite to the actual direction, since the acceleration is negative.
Mendeleev created a periodic table with 63 initial elements.
He left gaps for unknown elements.
To this date, there are 118 elements in the periodic table.