Answer:
259.274 kW
Explanation:
Given:
Area of the lava, A = 1.00 m²
Temperature of the surrounding, T₁ = 30.0° C = 303 k
Temperature of the lava, T₂ = 1190° C = 1463 K
emissivity, e = 1
Now,
from the Stefan-Boltzmann law of radiation the rate of heat loss is given as,
u = σeA(T₂⁴ - T₁⁴)
where,
u = rate of heat loss
σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m²∙K⁴
on substituting the respective values, we get
u = 5.67 × 10⁻⁸ × 1 × 1 × (1463⁴ - 303⁴)
or
u = 259274.957 W
or
u = 259.274 kW
We know that
• The sphere diameter is 8.55 cm.
,
• The temperature change is from 30 C to 155 C.
First, we have to find the radius of the sphere. The radius is the half diameter.

Now we have to find the volume of the sphere using the following formula.

Where r = 4.275 cm.

Then, we use the following formula

Where the initial volume is 327.26 cubic cm, B is a constant about thermal expansion for aluminum, and we have to find the final volume to then calculate the percentage change.

This means that the volume change is 3.07 cubic centimeters.
At last, we have to divide the volume change by the initial volume, and then we have to multiply it by 100% to express it as a percentage.

<h2>Therefore, the percentage change is 0.938%.</h2>
Answer:
when an object has more velocity, it tends to have less potential energy and more kinetic energy.
Explanation:
kinetic energy is the energy of movment and velocity helps to describe movement