Five kg of steam is contained within a piston-cylinder assembly.
It undergoes an expansion from state 1, where the specific
internal energy is 1 = 2709.9 kJ/kg to state 2, where 2 =
2659.6 kJ/kg. During the process, heat is transferred to the
steam with a magnitude of 80 kJ. Also, a paddle wheel transfers
energy to the steam by work in the amount of 18.5 kJ. There is
no significant change in the kinetic or potential energy of the
steam. Determine the energy transfer by work from the steam
to the piston during the process, in kJ. Indicate whether the
work is done on or done by the system.
when people invented new tools, they were able to go deeper. people explored deep caves beginning in the late nineteenth century. the hobbygained fame, or popularity, throughout the twentieth century. in the 1940s, cave explorers coined the term "spelunking" to describe the activity.
first, explain what a hobby is. then, explain which context clues helped you come up with your response.
please write your answer in complete sentences.
For me it seems that there is no test question,
Independent Variable: number of flowers.
Dependent Variable: different types of plants.
Control Variable: records
Polar bears can swim approximately 25 km in 3 h. How long would it take them to swim 15 m ?
We have the following data:
25 km = 25000 m
3 h = 3*(60min) = 180 min = 180*(60s) = 10800 s
Solving: Rule of three (directly proportional)
distance (m) ______ time (s)
25000 -------------------- 10800 s
15 -------------------------- y
multiply the means by the extremes
Polar bears would take about 6.5 seconds to swim for 15 m.
A balloon has a volume of 2,500ml on a day when the temperatureis 30°C. If the temperature at night falls to 10.0°C. What will be the volume of the balloon, if the pressure remains constant?
Note: in solving any gas law problems, kelvin temperature will be used.
kelvin = degree celsius + 273.15
Kelvin = 30°C + 273.15 = 303.15 K
Kelvin = 10°C + 273.15 = 283.15 K
V₁ (initial volume) = 2,500 ml V₂ (final volume) = ? unknown
T₁ (initial temperature = 30°C T₂ (final temperature) = 10 °C
= 303.15 K =283.15 K
This problem can be solve using Charles' Law which states that volume is directly proportional to kelvin temperature of gases if amount of gas and pressure are constant. If temperature decreases, volume decreases.
Formula of Charles' Law is V₁/T₁ = V₂/T₂
To solve for V₂, we can used the formula V₂ = V₁T₂ / T₁
V₂ = V₁T₂ / T₁
= 2,500 ml × 283.15 K / 303.15 K (cancel the unit kelvin)
= 707875 ml / 303.15
= 2335.065 ml
the volume of the balloon is 2335.065 ml