B.) Action and reaction forces helps during lift off of a rocket.
Hope this helps!
Answer:
The final temperature is 64.28°C.
Explanation:
Imagine now that one tried to repeat the same measurement, but between the time that the 400 cm³ of warm water was measured at 88°C and the time it was mixed with the 130 cm³ of cooler water at 15°C, the warmer water had lost 3060 cal to the environment. Calculate the final equilibrium temperature assuming no heat loss after mixing occurs.
Let the temperature of hot water before mixing is t
We need to calculate the temperature
Using formula of energy


Put the value into the formula




We need to calculate the final temperature
Using formula of temperature

Put the value into the formula


Hence, The final temperature is 64.28°C.
With the given information you can find the initial and final mechanical energies. Then we can verify the conservation of it.
1) Initially the ball is at rest 1 m over the ground, then its mechanical energy is only potential energy = m*g*h = 2kg * 9.8m/s^2 * 1m = 19.6 joule
2) When the ball is above to hit the ground, its mechanical energy is only kinetic energy = [1/2]m*v^2 = [1/2]2kg*(4.4m/s)^2 = 19.4 joule
Those results, taken into account that the measures have some errors (for example the exact velocity of the ball when it reaches de floor is quite difficult to measure) confirm the conservation of the energy.
Then, the answer is the option B. The mechanical energy is conserved