A bottle of water with mass 0.9 kg is left out in the sun, the radiation from the sun warms up the water bottle. If the water bottle was initially 10°C and the sun provided 120,000 J of thermal energy, calculate the final temperature of the water. Use C = 4182 j/kgK for the specific heat of water.

Final temperature, T2 = 314.9 Kelvin

Explanation:

Given the following data:

Mass = 0.9kg

Initial temperature, T1 = 10°C to Kelvin = 10 + 273 = 283K

Quantity of heat = 120,000 J

Specific heat capacity = 4182 j/kgK

To find the final temperature;

Heat capacity is given by the formula;

Where;

Q represents the heat capacity or quantity of heat.

m represents the mass of an object.

c represents the specific heat capacity of water.

dt represents the change in temperature.

Making dt the subject of formula, we have;

Substituting into the equation, we have;

dt = 31.9K

Now, the final temperature T2 is;

But, dt = T2 - T1

T2 = dt + T1

T2 = 31.9 + 283

T2 = 314.9 Kelvin

Explanation:

It is given that,

Mass of the parachutist, m = 100 kg

It falls from a height of 500 meters.

When the parachutist reaches the ground, the potential energy gets converted to its kinetic energy. The potential energy of the parachutist is given by the following formula as :

g is the acceleration due to gravity

Since, 1 kJ = 1000 J

So,

So, as the parachutist reaches ground its kinetic energy is equal to 490 kJ.