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3 years ago

A car, initially traveling at 15 meters per second

1 answer:

3 0

The magnitude of the acceleration of the car is given by:
$a= \frac{v_f-v_i}{t}$
where
$v_i=15 m/s$ is the initial speed of the car
$v_f=25 m/s$ is the final speed of the car
$t=4.0 s$ is the time it takes for the car to change its speed

Substituting these data into the formula, we find the magnitude of the average acceleration of the car:
$a= \frac{25 m/s-15 m/s}{4.0 s}=2.5 m/s^2$

therefore, the correct answer is (1) 2.5 m/s^2.

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How did tycho brahe's model of the universe differ from the greek geocentric model?

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4 0

4 years ago

Why is there no electric field at the center of a charged spherical conductor?

Alja [10]

I reported this question by accident, I am sorry.

Anyways, there is no electric field at the center of a charged spherical conductor because all the charged particles are at the edges and because of the complete cancellation everywhere.

5 0

4 years ago

A ball is thrown straight up in the air.When the ball reaches its highest point, which of the following is true?a. It is in equi

olasank [31]

Answer:

option E.

Explanation:

When the ball is at the highest point the velocity of the ball is zero.

At the height point the kinetic energy is zero and potential energy is maximum.

At maximum point momentum cannot be maximum because velocity is zero.

Acceleration on the ball is equal to acceleration due to gravity on the ball.

Hence, the correct answer is option E.

4 0

3 years ago

A student is experimenting with some insulated copper wire and a power supply. She winds a single layer of the wire on a tube wi

OverLord2011 [107]

Answer:

$P=214.7187\,W$

Explanation:

Given that:

Diameter of the solenoid, $D=10\,cm=0.1\,m$

length of the solenoid, $L=90\,cm=0.9\,m$

diameter of the wire, $d=0.1\,cm=10^{-3}\,m$

magnetic field at the center of the solenoid, $B=7.4\times 10^{-3}\,T$

Now we need the no. of turns incorporated in the length of 90 cm:

$N=\frac{Length\,\,of\,\,solenoid}{diameter\,\,of\,\, wire}$

$N=\frac{L}{d}$

$N=\frac{0.9}{10^{-3}}$

$N=900\,\,turns$

For solenoids we have:

$B=\mu.n.I$ ...............................(1)

where:

$\mu=$ permeability of the medium

n = no. of turns per unit length

I = current in the coil

So,

$n=\frac{900}{0.9}$

$n=1000\,turns\,.\,m^{-1}$

Now putting the respective values in the eq. (1)

$7.4\times 10^{-3}=4\pi\times10^{-7}\times 1000\times I$

$I=5.8887\,A$

For copper we have resistivity:

$\rho=1.72\times 10^{-8}\, \Omega.m$

We know that resistance is given by:

$R=\rho.\frac{l}{a}$ .....................................(2)

where:

l = length of the conducting wire

a = cross sectional area of the conducting wire

Now we need the length (l) of the wire:

Circumference of the solenoid,

$C=\pi.D$

$C=0.1\pi\,m$

$\therefore l=C\times N$

$l=90\pi\,m$

Cross-sectional area of wire:

$a=\pi.\frac{d^2}{4}$

$a=\pi. \frac{(10^{-3})^2}{4}\,m^2$

Resistance from eq. (2):

$R=1.72\times 10^{-8}\times \frac{90\pi}{\pi. \frac{(10^{-3})^2}{4}}$

$R=6.192 \,\Omega$

For power we have:

$P=I^2.R$

$P=5.8887^2 \times 6.192$

$P=214.7187\,W$

6 0

3 years ago

A transformer has two sets of coils, the primary with N1 = 160 turns and the secondary with N2 = 1400 turns. The input rms volta

vovikov84 [41]

To solve the problem it is necessary to apply the concepts related to the voltage in a coil, through the percentage relationship that exists between the voltage and the number of turns it has.

So things our data are given by

$N_1 = 160$