Answer: <em>Acceleration of the ball in the given system is 5 meter per Second Square</em>
<em>The laws of motion are used to determine various aspects of an object in motion</em>.
Explanation:
Applying the first law of motion to calculate acceleration; if formula used in first law is given as 
Here we have a final velocity as 40 meter per second and initial velocity as 20 meter per second and time span is given as 2 second applying the given values in the given equation and finding the value of a
The number of hydrogen atoms that are in 4.40 mol of ammonium sulfide is 2.12 x10^25 atoms
calculation
find the number of moles of Hydrogen in ammonium sulfide (NH4)2S
that is 4.40 x number of hydrogen atoms in (NH4)2S ( 4x2= 8 atoms)
moles is therefore= 4.40 x8= 35.2 moles
by use of Avogadro's law constant
that is 1mole = 6.02 x10^23 atoms
35.2 moles=?
by cross multiplication
{35.2 moles x 6.02 x10^23} /1 mole = 2.12 x10^25 atoms
The answer would be D. The only minerals harder than corundum is diamond.