Answer:
DU = 120 Joules
Explanation:
Given the following data;
Quantity of energy = 200 J
Work = 80 J
To find the change in internal energy;
Mathematically, the change in internal energy of a system is given by the formula;
DU = Q - W
Where;
DU is the change in internal energy.
Q is the quantity of energy.
W is the work done.
Substituting into the formula, we have;
DU = 200 - 80
DU = 120 Joules
Answer:
The average speed of the elevator going down in the abandoned mine is 17.722mph.
Explanation:
If the elevator takes 90 seconds to descend a height of 713m, the average speed of the elevator is:

And if 1m/s is 2.23694mph, the average speed is:
.
Answer:
When light travels from one medium to another, the frequency of light does not change. However, the velocity and wavelength change.
Explanation:
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Answer: The force needed is 140.22 Newtons.
Explanation:
The key assumption in this problem is that the acceleration is constant along the path of the barrel bringing the pellet from velocity 0 to 155 m/s. This means the velocity is linearly increasing in time.
The force exerted on the pellet is
F = m a
In order to calculate the acceleration, given the displacement d,

we will need to determine the time t it took for the pellet to make the distance through the barrel of 0.6m. That time can be determined using the average velocity of the pellet while traveling through the barrel. Since the velocity is a linear function of time, as mentioned above, the average is easy to calculate as:

This value can be used to determine the time for the pellet through the barrel:

Finally, we can use the above to calculate the force:

Answer:
1. Thermal Energy is the internal energy that is produced from the temperature of a heated substance/object.
2. From the potato to the soup and from the soup to the surrounding room
Explanation:
1. When an object or substance is heated it causes a rise in temperature which makes the atoms and molecules within the object move/vibrate faster and collide with each other. This kinetic energy energy comes from the temperature of the object being heated and is the thermal energy.
2. The atoms present in a hot object have higher kinetic energy when compared to a colder object and usually flow towards the colder object. This is why it is possible for the hot potato whose temperature is higher than the bowl of soup to flow towards the soup and from the soup to the surrounding room.