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3 years ago

A student uses an indicator to measure the pH of a solution. The indicator shows a pH of 7. What must be true of this solution?

Physics

1 answer:

Anna71 [15]3 years ago

3 0

Answer:

The solution is neither acidic or basic,

PH < 7 acidic

PH = 7 neutral

PH > 7 basic

It is a measure of the (H+) hydronium concentration.

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What is the period that corresponds to a frequency of 39.5 Hz? Answer in units of s.

tatiyna

The answer for the following problem is mentioned below.

Therefore the time period is 0.02 seconds.

Explanation:

Frequency:

The number of waves that pass a fixed place in a given amount of time. (or)

The number of waves that pas by per second.

The SI unit of the frequency is Hertz(Hz).

Time period:

The time taken for one complete cycle of vibration to pass a given point.

The SI unit of time period is seconds. (s)

Given:

Frequency (f) = 39.5 Hz

To calculate:

Time period (T)

We know;

According to the problem;

From the problem;

f = $\frac{1}{T}$

Where;

f represents the frequency

T represents the time period

f = $\frac{1}{39.5}$

f = 0.02 seconds

Therefore the time period is 0.02 seconds.

5 0

3 years ago

A machine does 50 J of Work on a 10 Kg Object. What is the Change in the Objects Total Energy?

Otrada [13]

The change in the total energy of the object is zero (0).

The given parameters:

work done by the machine, W = 50 J

mass of the object, m = 10 kg

To find:

the change in the total energy of the object

The change in the total energy of the object is the difference between the objects initial energy due to its position and the work done on the object.

Based on work energy-theory, the work done on the object is equal to the energy of the object.

The energy of the object = work-done on the object

The change in total energy = 50 J - 50 J = 0

Thus, the change in the total energy of the object is zero (0).

Learn more here: brainly.com/question/20377140

3 0

2 years ago

List 3 indicators that a chemical reaction has occurred.

mina [271]

Hello! There are many indicators to show a sign that a chemical reaction has occured. These are 3 as followed.

1. An odor is produced.

2. A change in temperature.

3. A color change.

Others can be a formation of a solid or a gas.

8 0

3 years ago

8. An unpowered flywheel is slowed by a constant frictional torque. At time t = 0 it has an angular velocity of 200 rad/s. Ten s

allsm [11]

Answer:

a) $\omega = 50\,\frac{rad}{s}$ , b) $\omega = 0\,\frac{rad}{s}$

Explanation:

The magnitude of torque is a form of moment, that is, a product of force and lever arm (distance), and force is the product of mass and acceleration for rotating systems with constant mass. That is:

$\tau = F \cdot r$

$\tau = m\cdot a \cdot r$

$\tau = m \cdot \alpha \cdot r^{2}$

Where $\alpha$ is the angular acceleration, which is constant as torque is constant. Angular deceleration experimented by the unpowered flywheel is:

$\alpha = \frac{170\,\frac{rad}{s} - 200\,\frac{rad}{s} }{10\,s}$

$\alpha = -3\,\frac{rad}{s^{2}}$

Now, angular velocities of the unpowered flywheel at 50 seconds and 100 seconds are, respectively:

a) t = 50 s.

$\omega = 200\,\frac{rad}{s} - \left(3\,\frac{rad}{s^{2}} \right) \cdot (50\,s)$

$\omega = 50\,\frac{rad}{s}$

b) t = 100 s.

Given that friction is of reactive nature. Frictional torque works on the unpowered flywheel until angular velocity is reduced to zero, whose instant is:

$t = \frac{0\,\frac{rad}{s}-200\,\frac{rad}{s} }{\left(-3\,\frac{rad}{s^{2}} \right)}$