<u>Answer:</u> The force that must be applied is 15 N.
<u>Explanation:</u>
Force exerted on the object is defined as the product of mass of the object and the acceleration of the object.
Mathematically,

where,
F = force exerted = ?
m = mass of the object = 3 kg
a = acceleration of the object = 
Putting values in above equation, we get:

Hence, the force that must be applied is 15 N.
Answer:
-75 cm^3/min
Explanation:
Given from Boyle's law;
PV=C
From product rule;
VdP/dt + PdV/dt = dC/dt
but dC/dt = 0, V= 500 cm^3, P= 200kPa, dP= 30kPa/min
PdV/dt = dC/dt - VdP/dt
dV/dt = dC/dt - VdP/dt/ P
substituting values;
dV/dt = 0 - (500 * 30)/200
dV/dt = -75 cm^3/min
Question
<em>Given the noble gas configuration of an element: [Ar] 4s2, 3d5, what is the element?
</em>
Answer:
<em>B.) Argon</em>
Hope this helps!