We must remember the definition of work, which says that work is equal to the product of mass by the distance displaced. In this case, the athlete only does work when he lifts the weight from the ground to the point where he holds the weight suspended.

So when he's holding the weight, he doesn't do any work.

3 0

3 years ago

__________ is the measure of the amount of disordered in a system

kolezko [41]

Entropy is the measure of the amount of disordered in a system.

<u>Explanation:</u>

In 1850, Entropy introduction by the German physicist Rudolf Clausius refers a measurement of the system's thermal energy in unit temperature. It is not for useful work because the work originates from ordered molecular motions. And, this also measures the molecular disturbance or randomness of the system.

The concept behind this provides deep view into spontaneous changes in many everyday phenomena’s. The idea of entropy is a mathematical way of coding an intuitive idea whose processes are impossible, and not violate the basic principle of energy conservation.

7 0

3 years ago

A 50-ω resistor is connected to a 9.0 V battery. How much thermal energy is produced in 7.5 minutes?1.2 * 10^2 J1.3 * 10^3 J3.0

emmasim [6.3K]

In order to calculate the thermal energy, first let's calculate the power, using the formula:

$P=\frac{V^2}{R}$

For a voltage V = 9 Volts and a resistance R = 50 ohms, we have:

$\begin{gathered} P=\frac{9^2}{50} \\ P=\frac{81}{50}=1.62\text{ W} \end{gathered}$

Now, multiplying the power by the time (in seconds), we can find the energy:

$\begin{gathered} E=P\cdot t \\ E=1.62\cdot7.5\cdot60 \\ E=729\text{ J} \end{gathered}$

In scientific notation, we have an energy of 7.3 * 10^2 J, therefore the correct option is the fourth one.

4 0

1 year ago

A child is holding a cup of hot tea. His mother, a physicist, warns him not to start running with the tea. According to Newton's

nalin [4]

If he stops running the tea is still going to be moving so it will spill on him.

3 0

3 years ago