Cereals are usually fortified with three most common minerals and vitamins which are:
1- Iron
2- Vitamin D
3- Vitamin B-12
Comparing the above to the given choices, we will find that the best answer is:
b. iron
A: Some physical properties change, but the substance keeps its identity.
Answer:
2 Hz.
Explanation:
Frequency is simply defined as the number of appearances of a periodic event occurring per time. It is usually measured in cycles/second.
Now, in this question, we are told that there are 2 cycles for each second.
Thus, we can say that the frequency is 2 cycles/1 s = 2 Hz.
<span>The force will be zero if the wagons are moving at a constant speed (i.e. not accelerating), as there is no frictional force to overcome. If the wagons are accelerating, the force will be proportional to the acceleration, and 20% of the force applied by A.</span>
