The law of energy conservation states that energy cannot be created or destroyed, so choices B to D are immediately invalid. Choice A can explain this occurrence: <u>A. Some of the energy is used to combat friction, and thus is transformed from mechanical energy to heat.</u>
mass of the ball m = 0.63 kg
initial height h = 1.8 m
final height h ' = 3.03 m
initial speed v = 7.09 m / s
final speed v ' = 4.21 m / s
Let the work done on the ball by air resistance W = ?
we know from law of conservation of energy ,
total energy at height h + work done by air = total energy at height h '
mgh + ( 1/ 2) mv^ 2 + W = mgh ' + ( 1/ 2) mv'^ 2
0.630*9.8*1.8 + 0.63*7.09^2 + W = mgh ' + ( 1/ 2) mv'^ 2
From there you can find W
if there is negative sign indicates it work opposite direction to motion
To answer this question, we must use the equation for the volumetric expansion of gases at constant pressure. This equation is given by:
We know:
is the initial volume 
ΔT is the temperature change = 45 ° -20 ° = 25 °
is the coefficient of gas expansion and is equal to 1/273
Then the final volume of the gas is:
Answer:
d. 149 ⁰C.
Explanation:
Given;
mass of the block of ice, m = 2 kg
specific heat capacity of the ice, C = 2090 J/(kgK)
initial temperature of the ice, t₁ = -90 ⁰C
heat added to the ice, H = 1,000,000 J
let the final temperature of the ice = t₂
The final temperature of the ice after adding the heat is calculated as follows;
Therefore, the new temperature of the water is 149 ⁰C.
