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3 years ago

Metals are good conductors of electricity because their protons can roam freely throughout the material. True False

Physics

1 answer:

cupoosta [38]3 years ago

7 0

Answer:

Explanation:

False

Electric conductivity in metals is the result of the motion of charged particles called electrons. Atoms of metallic elements are distinguished by the availability of valence electrons. Valence electrons are the electrons in the outer shell of an atom and free to move around.

These free electrons are free to move in the lattice of metal and result in electric current when a voltage is applied.

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A spring with spring constant 15.5 N/m hangs from the ceiling. A ball is suspended from the spring and allowed to come to rest.

Aloiza [94]

Answer:

A) 138.8g

B)73.97 cm/s

Explanation:

K = 15.5 Kn/m

A = 7 cm

N = 37 oscillations

tn = 20 seconds

A) In harmonic motion, we know that;

ω² = k/m and m = k/ω²

Also, angular frequency (ω) = 2π/T

Now, T is the time it takes to complete one oscillation.

So from the question, we can calculate T as;

T = 22/37.

Thus ;

ω = 2π/(22/37) = 10.5672

So,mass of ball (m) = k/ω² = 15.5/10.5672² = 0.1388kg or 138.8g

B) In simple harmonic motion, velocity is given as;

v(t) = vmax Sin (ωt + Φ)

It is from the derivative of;

v(t) = -Aω Sin (ωt + Φ)

So comparing the two equations of v(t), we can see that ;

vmax = Aω

Vmax = 7 x 10.5672 = 73.97 cm/s

6 0

2 years ago

A force of 450 N moves a body through 300 cm in the direction of force. Calculate the work

OlgaM077 [116]

Answer:

150J

Explanation:

Formula : Work done

Force x distance

work done = force x distance

Distance should be measured in meters

300÷100=3m

work done = 450 x 3

=150J

3 0

2 years ago

A flywheel turns through 40 rev as it slows from an angular speed of 1.5 rad/s to a stop.

Lynna [10]

Answer:

-0.0047 rad/s²

335.103 seconds

99.18 seconds

Explanation:

$\omega_f$ = Final angular velocity

$\omega_i$ = Initial angular velocity = 1.5 ra/s

$\alpha$ = Angular acceleration

$\theta$ = Angle of rotation = 40 rev

t = Time taken

Equation of rotational motion

$\omega_f^2-\omega_i^2=2\alpha \theta\\\Rightarrow \alpha=\frac{\omega_f^2-\omega_i^2}{2\theta}\\\Rightarrow \alpha=\frac{0^2-1.5^2}{2\times 2\pi \times 40}\\\Rightarrow \alpha=-0.0047\ rad/s^2$

Acceleration while slowing down is -0.0047 rad/s²

$t=\frac{\omega_f-\omega_i}{\alpha}\\\Rightarrow t=\frac{0-1.5}{-0.0047}\\\Rightarrow t=335.103\ s$

Time taken to slow down is 335.103 seconds

$\theta=\omega_it+\frac{1}{2}\alpha t^2\\\Rightarrow 20\times 2\pi=1.5\times t+\frac{1}{2}\times -0.0047\times t^2\\\Rightarrow 0.00235t^2-1.5t+125.66=0$

Solving the equation

$t=\frac{-\left(-1.5\right)+\sqrt{\left(-1.5\right)^2-4\cdot \:0.00235\cdot \:125.66}}{2\cdot \:0.00235}, \frac{-\left(-1.5\right)-\sqrt{\left(-1.5\right)^2-4\cdot \:0.00235\cdot \:125.66}}{2\cdot \:0.00235}\\\Rightarrow t=539.11, 99.18\ s$

The time required for it to complete the first 20 is 99.18 seconds as 539.11>335.103

4 0

2 years ago

5. Which of the following is velocity? *

ivann1987 [24]

A. 20m/s because the unit for velocity is m/s

3 0

2 years ago

The grounded conductor and the grounding conductor are one and the same conductor and perform the same function.

STALIN [3.7K]

Answer:

Grounded used to carry the current in the normal conditions. while on the other side grounding is refer to that safety wire that is connected to the earth and currently does not transmit through it.

As grounding wire is referred to as safety wire hence it carries current only in an emergency like a short circuit.

Explanation:

A grounded conductor is referred to as one of the wire that needed in an electric circuit. it is basically a neutral conductor. It used to carry the current in the normal conditions. while on the other side grounding is refer to that safety wire that is connected to the earth and currently does not transmit through it.

As grounding wire is referred to as safety wire hence it carries current only in an emergency like a short circuit.

5 0

2 years ago