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2 years ago

What is the velocity of a dropped object after it has fallen for 3.0 seconds?

1 answer:

3 0

As a consequence, gravity will accelerate a falling object so its velocity increases 9.81 m/s or 32 ft/sfor every second it experiences free fall. Velocity (v) can be calculated via v = gt, where g represents the acceleration due to gravity and t represents time in free fall.

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Do all metals expand the same amount when heated??

ahrayia [7]

Answer:

Explanation:

The rate at which solids expand when heated depends on the substance. Metals tend to have higher rates of expansion (per degree change in temperature) than non-metal solids, but there is variation even among metals. A table of expansion coefficients can be found here or here.

8 0

3 years ago

Read 2 more answers

A magnet is moved in and out of a coil of wire connected to a high-resistance voltmeter. If the number of coils doubles, the ind

Varvara68 [4.7K]

Answer:

A. Doubles.

Explanation:

In an electromagnetic device such as a generator, when a wire (conductor) moves through the magnetic field between the South and North poles of a magnet, an electromotive force (e.m.f) is usually induced across a wire

The mode of operation of a generator is that a metal core with copper tightly wound to it (conductor coil) rotates rapidly between the two (2) poles of a horseshoe magnet type. Thus when the conductor coil rotates rapidly, it cuts the magnetic field existing between the poles of the horseshoe magnet and then induces the flow of current.

When a high-resistance voltmeter is connected to an electric circuit, a deflection will arise due to the flow of electricity. Moving the magnet towards the coil of wire will cause the needle of the high-resistance voltmeter to move in one direction. Also, as the magnet is moved out from the coil of wire, the needle of the high-resistance voltmeter moves in the opposite direction.

In this scenario, a magnet is moved in and out of a coil of wire connected to a high-resistance voltmeter. If the number of coils doubles, the induced voltage doubles because the number of turns (voltage) in the primary winding is directly proportional to the number of turns (voltage) in the secondary winding.

4 0

2 years ago

A pulsar is a rapidly rotating neutron star. The Crab nebula pulsar in the constellation Taurus has a period of 33.5\times 10^{-

joja [24]

Answer:

$5.25\cdot 10^{40} kg m^2/s$

Explanation:

The angular momentum of the pulsar is given by:

$L=m\omega r^2$

where

$m=2.8\cdot 10^{30} kg$ is the mass of the pulsar

$r = 10.0 km = 1\cdot 10^4 m$ is the radius

$\omega$ is the angular speed

Given the period of the pulsar, $T=33.5\cdot 10^{-3} s$ , the angular speed is given by

$\omega=\frac{2\pi}{T}=\frac{2 \pi}{33.5\cdot 10^{-3}s}=187.5 rad/s$

And so, the angular momentum is

$L=m\omega r^2=(2.8\cdot 10^{30}kg)(187.5 rad/s)(1\cdot 10^4 m)^2=5.25\cdot 10^{40} kg m^2/s$

8 0

2 years ago

Establishing a potential difference The deflection plates in an oscilloscope are 10 cm by 2 cm with a gap distance of 1 mm. A 10

11111nata11111 [884]

Answer:

$1.62\times 10^{-8}\ \text{s}$

Explanation:

$\epsilon_0$ = Vacuum permittivity = $8.854\times 10^{-12}\ \text{F/m}$

$A$ = Area = $10\times 2\times 10^{-4}\ \text{m}^2$

$d$ = Distance between plates = 1 mm

$V_c$ = Changed voltage = 60 V

$V$ = Initial voltage = 100 V

$R$ = Resistance = $1000\ \Omega$

Capacitance is given by

$C=\dfrac{\epsilon_0A}{d}\\\Rightarrow C=\dfrac{8.854\times 10^{-12}\times 10\times 2\times 10^{-4}}{1\times 10^{-3}}\\\Rightarrow C=1.7708\times 10^{-11}\ \text{F}$

We have the relation

$V_c=V(1-e^{-\dfrac{t}{CR}})\\\Rightarrow e^{-\dfrac{t}{CR}}=1-\dfrac{V_c}{V}\\\Rightarrow -\dfrac{t}{CR}=\ln (1-\dfrac{V_c}{V})\\\Rightarrow t=-CR\ln (1-\dfrac{V_c}{V})\\\Rightarrow t=-1.7708\times 10^{-11}\times 1000\ln(1-\dfrac{60}{100})\\\Rightarrow t=1.62\times 10^{-8}\ \text{s}$

The time taken for the potential difference to reach the required level is $1.62\times 10^{-8}\ \text{s}$ .

5 0

2 years ago

What kind of lens is there in our eyes? where does it form the image of an object?

Goshia [24]

Answer:

convex lens

Explanation:

An image is form in retina with light rays converging most at cornea and upon entering and existing the lens.Rays from top and bottom of the object are traced and produce an inverted image on the retina

8 0

2 years ago