Physics help! I really need this homework done:

A 10-foot ladder is leaning straight up against a wall when a person begins pulling the base of the ladder away from the wall at

docker41 [41]

Answer:

$y = 4.36$

Explanation:

Let the height of the ladder be L

$L = 10$

Also:

Let $x = distance\ from\ the\ base\ of\ the\ ladder$

Let $y = height\ of\ the\ base\ of\ the\ ladder$

When the ladder leans against the wall, it forms a triangle and the length of the ladder forms the hypotenuse.

So, we have:

$L^2 = x^2 + y^2$ --- Pythagoras Theorem

When the base is 9ft from the wall, this means that:

$x = 9$

Substitute 9 for x and 10 for L in $L^2 = x^2 + y^2$

$10^2 = 9^2 + y^2$

$100 = 81 + y^2$

Make $y^2$ the subject

$y^2 = 100 - 81$

$y^2 = 19$

Make y the subject

$y = \sqrt{19$

$y = 4.36$

<em>Hence, the true distance at that point is approximately 4.36ft</em>

8 0

3 years ago

An electric dipole consisting of charges of magnitude 1.70 nC separated by 6.80 μm is in an electric field of strength 1160 N/C.

bazaltina [42]

Answer:

p = 1.16 10⁻¹⁴ C m and ΔU = 2.7 10 -11 J

Explanation:

The dipole moment of a dipole is the product of charges by distance

p = 2 a q

With 2a the distance between the charges and the magnitude of the charges

p = 1.7 10⁻⁹ 6.8 10⁻⁶

p = 1.16 10⁻¹⁴ C m

The potential energie dipole is described by the expression

U = - p E cos θ

Where θ is the angle between the dipole and the electric field, the zero value of the potential energy is located for when the dipole is perpendicular to the electric field line

Orientation parallel to the field

θ = 0º

U = 1.16 10⁻¹⁴ 1160 cos 0

U1 = 1.35 10⁻¹¹ J

Antiparallel orientation

θ = 180º

cos 180 = -1

U2 = -1.35 10⁻¹¹ J

The difference in energy between these two configurations is the subtraction of the energies

ΔU = | U1 -U2 |

ΔU = 1.35 10-11 - (-1.35 10-11)

ΔU = 2.7 10 -11 J

6 0

3 years ago

Random kinetic energy possessed by objects in a material at finite temperature. An object that feels hot has a lot of this.

gregori [183]

Internal energy or thermal energy.

3 0

3 years ago

Read 2 more answers

Communication with submerged submarines via radio waves is difﬁcult because seawater is conductive and absorbselectromagnetic wa

FrozenT [24]

Answer:

D. 4000 km

Explanation:

f = Frequency of wave that is being transmitted = 76 Hz

$\lambda$ = Wavelength of wave that is being transmitted

v = The velocity of electromagnetic waves through air = $3\times 10^8\ m/s$

Velocity of a wave is given by

$v=f\lambda\\\Rightarrow \lambda=\frac{v}{f}\\\Rightarrow \lambda=\frac{3\times 10^8}{76}\\\Rightarrow \lambda=3947368.42105\ m=3947.36842105 km\approx 4000\ km$

Hence, the approximate wavelength of the waves is 4000 km

8 0

3 years ago

A student weighing 700 N climbs at constant speed to the top of an 8 m vertical rope in 10 s. The average power expended by the

Goshia [24]

To solve this problem we will use the concepts related to power, defined as the amount of energy applied over a period of time.

The energy in this case is the accumulated in the form of potential energy, over a period of time. Thus we will have that the mathematical expression of the power can be expressed as

$P = \frac{E}{t}$