A32.5 g iron rod, initially at 21.8°c, is submerged into an unknown mass of water at 63.3°c, in an insulated container. the final temperature of the mixture upon reaching thermal equilibrium is 58.9°c. what is the mass of the water?

the mass of the water is 29.4 g

Explanation:

given information:

mass of iron, = 32.5 g

iron's temperature, = 21.8°C

water's temperature, = 63.3°C

thermal equilibrium, = 58.9°C

since water and iron is being mixed, q of the water and the iron are equal, thus

= - , heat being transfer

Δ =tex]m_{w}[/tex] Δ

(32.5)(0.449)(58.9-21.8) = tex]m_{w}[/tex] (4.18)(58.9-63.3)

tex]m_{w}[/tex] = (32.5)(0.449)(58.9-21.8)/(4.18)(58.9-63.3)

  = 29.4 g

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.