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2 years ago

15

Al llegar a detenerse, un automóvil deja marcas de derrape de 92m de largo sobre una autopista. Si se supone una desaceleración

de 7 m/s, estime la rapidez del automóvil justo antes de frenar

1 answer:

Bezzdna [24]2 years ago

8 0

Answer:

Explanation: no se español

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7) Three resistors having resistances of 4.0 Ω, 6.0 Ω, and 10.0 Ω are connected in parallel. If the combination is connected in

viva [34]

Answer:

A, 0.59A

Explanation:

The total resistance in the circuit is the resistances in parallel plus that in series.

Total resistance for those in parallel is;

1/(1/4 +1/6 +1/10) = 1/ (15+10+6 /60)

1/(31/60)= 60/31 ohms

Hence total resistance of the circuit is;

60/31 + 2 = (60+62)/31 = 122/31=3.94 ohms

To calculate the current flowing through the 10ohm resistance we need to know the voltage drop by subtracting the voltage drop in the 2ohm resistance from the total voltage drop.

Voltage drop on the 2 ohm resistance is;

Current on the 2 ohm resistor × 2 ohms

V = I ×R ; I - current

R - resistance

Current drop on the 2ohm resistance is;

Total voltage in the circuit/ total resistance in the circuit

12/3.94= 3.05A

Voltage drop on the 2 ohm resistance;

3.05 × 2 = 6.10volts

Hence voltage drop on the parallel resistance would be ;

12-6.10= 5.90V

Now voltage drop in a parallel circuit is the same hence 5.90v is dropped in each of the parallel resistance.

That said, the current drop on the 10 ohm resistor would be;

5.90/10 = 0.59A

Remember V= I× R so that I = V/R

6 0

2 years ago

If a sound with frequency fs is produced by a source traveling along a line with speed vs. If an observer is traveling with spee

Alexus [3.1K]

Answer:

457.81 Hz

Explanation:

From the question, it is stated that it is a question under Doppler effect.

As a result, we use this form

fo = (c + vo) / (c - vs) × fs

fo = observed frequency by observer =?

c = speed of sound = 332 m/s

vo = velocity of observer relative to source = 45 m/s

vs = velocity of source relative to observer = - 46 m/s ( it is taking a negative sign because the velocity of the source is in opposite direction to the observer).

fs = frequency of sound wave by source = 459 Hz

By substituting the the values to the equation, we have

fo = (332 + 45) / (332 - (-46)) × 459

fo = (377/ 332 + 46) × 459

fo = (377/ 378) × 459

fo = 0.9974 × 459

fo = 457.81 Hz

7 0

2 years ago

Is v2 = v1t+a dimensionally correct? Explain please!

Lady bird [3.3K]

You want v2 = v1 + at
v is measured in m/s, a in m/s2, and t in s.
the dimensions multiply like algebraic quantities.
so because v2 is measured in m/s, then (v1 + at) has to come out in m/s
the units for (v1 + at) are (m/s) + (m/s2)(s)
time "s" cancels out one acceleration "s", so it comes ut to (m/s) + (m/s), which = (m/s).
if you had (v1t + a), then you would have (m/s)(s) + (m/s2) which = (m) + (m/s2), which doesn't work.

4 0

2 years ago

A windowpane is half a centimeter thick and has an area of 1.0 m2. The temperature difference between the inside and outside sur

polet [3.4K]

To solve this problem it is necessary to apply the concepts related to the heat flux rate expressed in energetic terms. The rate of heat flow is the amount of heat that is transferred per unit of time in some material. Mathematically it can be expressed as:

$\frac{Q}{t} = \frac{kA}{L} (T_H - T_C)$

Where

k = 0.84 J/s⋅m⋅°C (The thermal conductivity of the material)

$A = 1m^2$ Area

$L = 5*10^{-3}m$ Length

$T_H$ = Temperature of the "hot"reservoir

$T_C$ = Temperature of the "cold"reservoir

Replacing with our values we have that,

$\frac{Q}{t} = \frac{kA}{L} (T_H - T_C)$

$\frac{Q}{t} = \frac{(0.84)(1)}{0.005} (15)$

$\frac{Q}{t} = 2520J/s$

Therefore the correct answer is B.

3 0

2 years ago

Medical cyclotrons need efficient sources of protons to inject into their center. In one kind of ion source, hydrogen atoms (i.e

Arlecino [84]

Answer:

The radius is $r = 4.434 *10^{-5} \ m$

Explanation:

From the question we are told that

The magnetic field is $B = 90 mT = 90*10^{-3} \ T$

The electron kinetic energy is $KE = 1.4 eV = 1.4 * (1.60*10^{-19}) =2.24*10^{-19} \ J$

Generally for the collision to occur the centripetal force of the electron in it orbit is equal to the magnetic force applied

This is mathematically represented as

$\frac{mv^2}{r} = qvB$

=> $r = \frac{m* v}{q * B}$

Where m is the mass of electron with values $m = 9.1 *10^{-31} \ kg$

v is the escape velocity which is mathematically represented as

$v = \sqrt{\frac{2 * KE}{m} }$

So

$r = \frac{m}{qB} * \sqrt{\frac{2 * KE}{m} }$

apply indices

$r = \frac{\sqrt{2 * KE * m} }{qB}$

substituting values

$r = \frac{\sqrt{2 * 2.24*10^{-19}* 9.1 *10^{-31}} }{ 1.60 *10^{-19}* 90*10^{-3}}$

$r = 4.434 *10^{-5} \ m$

6 0

1 year ago