The similarity is that they both are types of bonds in molecules.
Ionic bonds are between a metal and a nonmetal.
Covalent bonds are between two nonmetals.
Answer: 4
Explanation: speed= distance/time
Answer:
They both tend to develop during the spring (March-June), reach peak intensity during the late autumn or winter (November-February), and then weaken during the spring or early summer (March-June)
Answer:
Approximately 
, assuming friction between the vehicle and the ground is negligible.
Explanation:
Let 
denote the mass of the vehicle. Let 
denote the initial velocity of the vehicle. Let 
denote the spring constant (needs to be found.) Let 
denote the maximum displacement of the spring.
Convert velocity of the vehicle to standard units (meters per second):
.
Initial kinetic energy (
) of the vehicle:
.
When the vehicle is brought to a rest, the elastic potential energy (
) stored in the spring would be:
.
By the conservation of energy, if the friction between the vehicle and the ground is negligible, the initial 
of the vehicle should be equal to the 
of the vehicle. In other words:
.
Rearrange this equation to find an expression for , the spring constant:
.
Substitute in the given values 
, 
, and 
:
