What factors affect the survival and change(evolution) of species over time?

A 50kg box is pulled on by a rope. The rope applies a horizontal force of 180 N to the box. What is the normal force exerted on

Over [174]

The normal force would be the opposing and equal force to gravity ... that is why the box isn't floating or going through the ground ... this is Newton's third law of motion

4 0

4 years ago

A rear window defroster consists of a long, flat wire bonded to the inside surface of the window. When current passes through th

GenaCL600 [577]

Answer:

$\rho=1.8\times 10^{-8}\Omega.m$

Explanation:

Given:

width of the wire, $w=1.8\ mm=1.8\times 10^{-3}\ m$

thickness of the flat wire, $d=0.12\ mm=1.2\times 10^{-4}$

length of the wire, $l=12\ m$

voltage across the wire, $V=12\ V$

current through the wire, $I=12\ A$

Now the net resistance of the wire:

using ohm's law

$R=\frac{V}{I}$

$R=\frac{12}{12}$

$R=1\ \Omega$

We have the relation between the resistivity and the resistance as:

$R=\rho.\frac{l}{a}$

where:

a = cross sectional area of the wire

$\rho =$ resistivity of the wire material

$1=\rho\times \frac{12}{1.8\times 10^{-3}\times 1.2\times 10^{-4}}$

$\rho=1.8\times 10^{-8}\Omega.m$

4 0

4 years ago

The following represents a mass attached to a spring oscillating in simple harmonic motion. X(t) = 4.0 cos(3.0t +0.10) units of

kolbaska11 [484]

Answer:

a) A = 4.0 m , b) w = 3.0 rad / s , c) f = 0.477 Hz , d) T = 20.94 s

Explanation:

The equation that describes the oscillatory motion is

x = A cos (wt + fi)

In the exercise we are told that the expression is

x = 4.0 cos (3.0 t + 0.10)

let's answer the different questions

a) the amplitude is

A = 4.0 m

b) the frequency or angular velocity

w = 3.0 rad / s

c) angular velocity and frequency are related

w = 2π f

f = w / 2π

f = 3 / 2π

f = 0.477 Hz

d) the period

frequency and period are related

T = 1 / f

T = 1 / 0.477

T = 20.94 s

e) the phase constant

Ф = 0.10 rad

f) velocity is defined by

v = dx / dt

v = - A w sin (wt + Ф)

speed is maximum when sine is + -1

v = A w

v = 4 3

v = 12 m / s

g) the angular velocity is

w² = k / m

k = m w²

k = 1.2 3²

k = 10.8 N / m

h) the total energy of the oscillator is

Em = ½ k A²

Em = ½ 10.8 4²

Em = 43.2 J

i) the potential energy is

Ke = ½ k x²

for t = 0 x = 4 cos (0 + 0.1)

x = 3.98 m

j) kinetic energy

K = ½ m v²

for t = 00.1 ²

v = A w sin 0.10

v = 4 3 sin 0.10

v = 1.98 m / s

3 0

3 years ago

1) Halving the distance (i.s., decreasing by a factor of two) between two charged objects will cause the electrical force betwee

Vedmedyk [2.9K]

Answer:

Explanation:

For an electric force, F the formula:

F = kQq/r^2

Given:

r2 = 1/2 × r1

F1 × r1 = k

F1 × r1 = F2 × r2

F2 = (F1 × r1^2)/(0.5 × r1)^2

= (F1 × r1^2)/0.25r1^2

= 4 × F1.

7 0

4 years ago

A parallel RLC circuit contains an inductor with a value of 400 microhenries and a capacitor with a value of 0.3 microfarads wha

ipn [44]

Answer:

The resonant frequency of this circuit is 14.5 kHz.

Explanation:

Given that,

Inductance of a parallel LCR circuit, $L=400\ \mu H=400\times 10^{-6}\ H$

Capacitance of parallel LCR circuit, $C=0.3\ \mu F=0.3\times 10^{-6}\ F$

At resonance the inductive reactance becomes equal to the capacitive reactance. The resonant frequency is given by :

$f=\dfrac{1}{2\pi \sqrt{LC} }$

$f=\dfrac{1}{2\pi \sqrt{400\times 10^{-6}\times 0.3\times 10^{-6}} }$

$f=14528.79\ Hz$

or

f = 14.5 kHz

So, the resonant frequency of this circuit is 14.5 kHz. Hence, this is the required solution.

4 0

3 years ago