OA the speed will increase four times
Answer:
His acceleration is
Explanation:
Newton's second law states that acceleration of a body is cause by a net force, the relation between them is:

On the boy there're acting two forces, his weight (W) that points downward and the frictional force (f) that points upward (they boy moves downward and friction always is opposite to movement). So
so (1) is:

Using the positive direction downward weight and gravitational acceleration(g) are positive and friction force is negative:
, solving for a:
, weight is mg:


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