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3 years ago

How much work does a motor do as it lifts a 675-kilogram elevator from a height of 15 meters to a height of 35 meters?

1 answer:

3 0

Work is defined as Force x Distance

W = Fd

so (675kg)(9.8m/s^2) = 6615 N

d = 35-15 = 20m

so

W = Fd
(6615N)(20m)

132,300 J = W

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In a certain oscillating LC circuit, the total energy is converted from electrical energy in the capacitor to magnetic energy in

aleksandrvk [35]

Answer:

A = 5.6μs

B = 178.57kHz

C = 2.8μs

Explanation:

A. It takes ¼ of the period of the circuit before the total energy is converted from electrical energy in the capacitor to magnetic energy in the inductor.

t = T/4

T = 4*t

T = 4 * 1.4 = 5.6μs

B. f = 1/T

Frequency is the inverse of period

f = 1 / 5.6*10⁻⁶

f = 178571.4286Hz

f = 178.57kHz

C. time taken for maximum energy to occur is T/2

t = 5.6 / 2 = 2.8μs

5 0

3 years ago

A string exerts a force of 20 N on a box at an angle of 38° from the horizontal. What is the horizontal component of the force o

dem82 [27]

Answer:

15.8 N

Explanation:

The component in a given direction is the magnitude of the applied force, multiplied by the cosine of the angle between its application and the direction of interest.

The horizontal component is ...

(20 N)cos(38°) ≈ 15.8 N

7 0

3 years ago

Read 2 more answers

A four-wheel-drive vehicle is transporting an injured hiker to the hospital from a point that is 30 km from the nearest point on

zepelin [54]

Answer:

$D=200\ km$

Explanation:

distance on terrain, $d_t=30\ km$

distance on the road, $d_r=70\ km$

speed on terrain, $v_t=30\ km.hr^{-1}$

speed on road, $v_r=130\ km.hr^{-1}$

<u>time taken on the terrain,</u>

$t_t=\frac{d_t}{v_t}$

$t_t=\frac{30}{30}$

$t_t=1\ hr$

<u>time taken to cover the distance on the road:</u>

$t_r=\frac{d_r}{v_r}$

$t_r=\frac{70}{130}$

$t_r=\frac{7}{13}\ hr$

<u>Now the distance covered on terrain in the total time:</u>

$D= v_r\times (t_r+t_t)$

$D= 130\times (\frac{7}{13}+1)$

$D=130\times \frac{20}{13}\$

$D=200\ km$

<em>is the distance the vehicle must target on the road to minimize the time taken in going off the road.</em>

3 0

3 years ago

(b) A Blu-ray laser has a power of 5 milliwatts (1 watt = 1 J s−1). How many photons of light are produced by the laser in 1 hou

worty [1.4K]

Answer:

The number of photons of light produced by the laser in 1 hour is

1 Photon / hour

Explanation:

Number of photons of light produced is given by

$Number of photons = \frac{Power}{Energy}$

From the question,

Power = 5 mW (milliwatts) = 5 × 10⁻³ W

Since 1 Watt = 1 Js⁻¹

Then, 5 × 10⁻³ W = 5 × 10⁻³ Js⁻¹

For the Energy,

As given from the question

Energy=(Power)x(time)

Time = 1 hour = (1 × 60 × 60) s = 3600 s

∴ Energy = 5 × 10⁻³ Js⁻¹ x 1 x 3600s

Energy =18.0 J

Now for the Number of photons produced,

$Number of photons = \frac{Power}{Energy}$

Power = 5 × 10⁻³ Js⁻¹ = 0.005 Js⁻¹

$Number of photons = \frac{0.005}{18}$

Number of photons = 2.78 × 10⁻⁴ Photons / sec

This is the number of photons produced in 1 second.

For the number of photons produced in 1 hour, we will multiply the result by 3600

(NOTE: 1 sec = $\frac{1}{3600}$ hour)

Number of photons = 2.78 × 10⁻⁴ Photons / sec

= 2.78 × 10⁻⁴ × 3600 Photons / hour

= 1.0008 Photons / hour

≅ 1 Photon / hour

Hence, the number of photons of light produced by the laser in 1 hour is

1 Photon / hour

5 0

3 years ago

Which of the following is the best paraphrasing of the Heisenberg uncertainty principle? Which of the following is the best para

weqwewe [10]

<h2>Answer:The more precisely you know the position of a particle, the less well you can know the momentum of the particle</h2>

The Heisenberg uncertainty principle was enunciated in 1927. It postulates that the fact that each particle has a wave associated with it, imposes <u>restrictions on the ability to determine its position and speed at the same time. </u>

In other words:

It is impossible to measure simultaneously (according to quantum physics), and with absolute precision, the value of the position and the momentum (linear momentum) of a particle.

<h2>So, the greater certainty is seeked in determining the position of a particle, the less is known its linear momentum and, therefore, its mass and velocity. </h2><h2 />

In fact, even with the most precise devices, the uncertainty in the measurement continues to exist. Thus, in general, the greater the precision in the measurement of one of these magnitudes, the greater the uncertainty in the measure of the other complementary variable.

4 0

3 years ago