Explanation:
At the maximum height, the ball's velocity is 0.
v² = v₀² + 2a(x - x₀)
(0 m/s)² = (12.3 m/s)² + 2(-9.80 m/s²)(x - 0 m)
x = 7.72 m
The ball reaches a maximum height of 7.72 m.
The times where the ball passes through half that height is:
x = x₀ + v₀ t + ½ at²
(7.72 m / 2) = (0 m) + (12.3 m/s) t + ½ (-9.8 m/s²) t²
3.86 = 12.3 t - 4.9 t²
4.9 t² - 12.3 t + 3.86 = 0
Using quadratic formula:
t = [ -b ± √(b² - 4ac) ] / 2a
t = [ 12.3 ± √(12.3² - 4(4.9)(3.86)) ] / 9.8
t = 0.368, 2.14
The ball reaches half the maximum height after 0.368 seconds and after 2.14 seconds.
A heat pump is a device used to heat something, in this case water. Heat pump takes heat from colder object and transfers it to warmer object. This is opposite to <span>direction of spontaneous heat transfer which from warmer to colder object.
In this problem a room got colder while water got warmer. This is due to work done by heat pump. This is what is described in correct answer c).
a) is not correct because it shows </span>direction of spontaneous heat transfer. It also says that <span>Aleksei’s family purchased a new water heater and in description givne in a) it would mean that water got colder.
b) is not correct because if the </span><span>burning fuel increased the thermal energy in the air it would mean that this room got warmer than rest of house.
d) is not correct because burning fuel does not absorb </span><span>thermal energy. It releases it.</span>
Answer:
D
Explanation:
he describes as he writes them down
A Framework for K–12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (Framework) recommends science education in grades K–12 be built around three major dimensions: science and engineering practices, crosscutting concepts that unify the study of science and engineering through their common application across fields, and core ideas in the major disciplines of natural science.
