Answer:
2500 J
Explanation:
We can solve the problem by using the first law of thermodynamics:
where
Uf is the final internal energy of the system
Ui is the initial internal energy
Q is the heat added to the system
W is the work done by the system
In this problem, we have:
Q = +1000 J (heat that enters the system)
W = +500 J (work done by the system)
Ui = 2000 J (initial internal energy)
Using these numbers, we can re-arrange the equation to calculate the final internal energy:
The answer for the online test is going to be the last one, D
<span>So we want to know which of the following is the best representation of converting potential energy into kinetic energy. The correct answer is C. A roller coaster rounds a curve to climb the next hill. So before he climbed the hill, the roller coaster had kinetic energy which he used to climb to the hill. Then the potential energy he has on the hill can again be transformed into kinetic energy when he will go down hill. </span>
Answer:
when the temperatures of the two objects are equal
Explanation:
Thermal equilibrium is achieved between two objects when the temperatures of the two objects are equal. Heat flows from hot to cold objects. When the two objects attain equal temperatures, we say thermal equilibrium has been achieved
Answer:
Explanation:
Given the height reached by a balloon after t sec modeled by the equation
h=1/2t²+1/2t
a) To calculate the height of the balloon after 40 secs we will substitute t = 40 into the modeled equation and calculate the value of t
If h(t)=1/2t²+1/2t
h(40) = 1/2(40)²+1/2 (40)
h(40) = 1600/2 + 40/2
h(40) = 800 + 20
h(40) = 820 feet
The height of the balloon after 40 secs is 820 feet
b) Velocity is the change of displacement of a body with respect to time.
v = dh/dt
v(t) = 2(1/2)t²⁻¹ + 1/2
v(t) = t + 1/2
when v = 0sec
v(0) = 0 + 1/2
v(0) = 1/2 ft/sec
at v = 30secs
v(30) = 30 + 1/2
v(30) = 30 1/2 ft/sec
average velocity = v(30) - v(0)
average velocity = 30 1/2 - 1/2
average velocity of the balloon between t = 0 and t = 30 = 30 ft/sec
c) Velocity is the change of displacement of a body with respect to time.
v = dh/dt
v(t) = 2(1/2)t²⁻¹ + 1/2
v(t) = t + 1/2
The velocity of the balloon after 30secs will be;
v(30) = 30+1/2
v(30) = 30.5ft/sec
The velocity of the balloon after 30 secs is 30.5 feet/sec
