1. What is the new kinetic energy of the 1900kg ship on the right moving at 4 m/s?

A current flowing through you of more than 5 ma is considered dangerous. Why do we see warnings about high voltage, rather than

svet-max [94.6K]

Answer:

V = 500 volts

I = 50 nA

Explanation:

We usually see 'high voltage' sign rather than 'high current' this is due to the fact that the amount of current depends upon the resistance of the body,

The relation of voltage, current and resistance is given by Ohm's law,

V = IR

I = V/R

As you can see, current and resistance are inversely related, the lower the resistance of the body, the higher will be the current flowing through the body.

What voltages are dangerous even if the skin is dry?

A dry human body has a resistance of approximately 100 kΩ and it gets reduced if the body is wet.

For a current of 5 mA, the corresponding voltage is,

V = 0.005*100,000

V = 500 volts

Therefore, for a dry human body, a voltage of 500 volts would be dangerous.

If voltage differences that are observed are about 0.5 mV, and the resistance of the skin is about 10 kΩ, what size currents are involved?

I = V/R

I = 0.0005/10,000

I = 50×10⁻⁹ A

I = 50 nA

Therefore, a current of 50 nA would be flowing through the EEG.

8 0

3 years ago

A fire engine is rapidly approaching you at a stop light. What happens to the frequency and pitch of the sound as the fire engin

ValentinkaMS [17]

Answer:

The frequency increases, and the pitch increases

Explanation:

Doppler's law of sound is applicable in such case when the observer or the sound source or both are moving relative to each other.

In such a case due to space-time constraint the waveform of the sound adjust themselves so as to obey the law of conservation of energy.

<u>The apparent frequency of the sound for the observer is given by:</u>

$f_o=(\frac{s+v_o}{s+v_s} )f$ ....................................(1)

where:

$f_o=$ observed frequency

$f=$ original source frequency

$s=$ speed of sound

$v_s=$ speed of source relative to the observer (taken negative when approaching towards the observer and vice-versa)

$v_o=$ speed of observer relative to the source (taken negative when moving away from the source and vice-versa)

<u>According to the given situation, eq. (1) becomes:</u>

$f_o=(\frac{s}{s-v_s} )f$

Since, $\frac{s}{s-v_s} >1$

Therefore

$f_o>f$

Pitch is very closely related to the frequency, it means that how fast is the amplitude of sound varying with time.

7 0

3 years ago

The position of a 55 g oscillating mass is given by x(t)=(2.0cm)cos(10t), where t is in seconds. determine the velocity at t=0.4

NNADVOKAT [17]

The position of the mass is given by (in cm):
$x(t)=2 \cos (10 t)$
The velocity is the derivative of the position:
$v(t) = \frac{dx(t)}{dt} =-10\cdot 2 \sin (10t)=-20 \sin (10t)$
Substituting t=0.40 s, we can find the velocity at this time:
$v(0.40 s)= -20 \sin (10 \cdot 0.4)=15 cm/s=15 \cdot 10^{-2}m/s$

5 0

3 years ago

Read 2 more answers

Why do different substances produce electromagnetic waves when they are heated up or energized?

Anit [1.1K]

Answer:

Electromagnetic radiation is made when an atom absorbs energy. The absorbed energy causes one or more electrons to change their locale within the atom. When the electron returns to its original position, an electromagnetic wave is produced. ... These electrons in these atoms are then in a high energy state.

Explanation:

4 0

4 years ago

Read 2 more answers

What causes small grain igneous rock to form? What causes large -grained igneous rock to form

Lunna [17]

Weather the rock was formed above ground or below ground

I hope this helped:)

7 0

3 years ago