Answer:
Because alkali metals are so reactive, they are found in nature only in combination with other elements. They often combine with group 17 elements, which are very “eager” to gain an electron.
Explanation:
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|Momentum| = (mass) x (speed)
225 kg-m/s =(50kg) x (speed)
Divide each side by (50kg): Speed=(225 kg-m/s) / (50 kg) = 4.5 m/s .
Regarding the velocity, nothing can be said other than the speed, because
we have no information regarding the direction of the object's motion.
The correct answer is:
<span>The rate at which a waves energy flows through a given unit of area
In fact, light intensity is defined as the light power per unit of area:
</span>

<span>but the power is the energy carried by the light per unit of time:
</span>

<span>this means that the intensity can be rewritten as
</span>

<span>
So, it's basically the rate of energy (per unit of time) through a given surface.</span>
Answer:
Elastic potential energy, E = 200 J
Explanation:
It is given that,
Spring constant, K = 4 N/m
initial stretching in the spring, x = 5 m
Finally, it is stretched an additional 5 m i.e. x' = 5 m
Let E is the elastic energy in the spring after Varg stretches the spring. it is given by :


E = 200 J
So, the elastic energy in the spring after Varg stretches the spring is 200 J. hence, this is the required solution.