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2 years ago

10

A 40-kg person is climbing 3 m up a flight of stairs in 6 seconds. How much work did they do climbing the stairs? (acceleration

due to gravity = 10 m/sec2)

1 answer:

iVinArrow [24]2 years ago

5 0

Answer:

1200J

Explanation:

W.D=mass×accelerarion due to gravity×distance

W.D=40kg×10m/s²×3m

W.D=1200kgm²/s²

W.D=1200J

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As soon as parachute of a falling soldier opens, how will the accleration change?

WITCHER [35]

Answer:

The acceleration will become zero

Explanation:

When the parachute of a falling soldier is opened the wide surface area decreases his velocity. This also translates to the drag force acting on the fallen soldier

The acceleration will become zero when the velocity of the fallen soldier is constant. This principle is the reason the parachute is used for safety reasons .

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2 years ago

If a copper tube has current flowing to the right in the presence of a magnetic field going forward ("into the board"), we expec

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Answer:

False, because current flow has no effect in the weight of a conductor.

Explanation:

Current flow has no effect in the weight of a conductor. Thus, the weight on the scale will be the same when current is flowing and when current is not flowing in the copper tube.

Therefore, If a copper tube has current flowing to the right in the presence of a magnetic field going forward ("into the board"), we expect the weight on the scale to be the same whether current is flowing or not.

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3 years ago

A camera flash, which throws a parallel beam of light, has a mirror behind the light bulb. What kind of mirror is it likely to b

WINSTONCH [101]

For Plato, the correct answer is Concave mirror :)

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3 years ago

Read 2 more answers

Write equations for both the electric and magnetic fields for an electromagnetic wave in the red part of the visible spectrum th

Strike441 [17]

Answer:

$E=3.5(8.98*10^{6}x-2.69*10^{15}t)$

$B=1.17*10^{-8}(8.98*10^{6}x-2.69*10^{15}t)$

Explanation:

The electric field equation of a electromagnetic wave is given by:

$E=E_{max}(kx-\omega t)$ (1)

E(max) is the maximun value of E, it means the amplitude of the wave.
k is the wave number
ω is the angular frequency

We know that the wave length is λ = 700 nm and the peak electric field magnitude of 3.5 V/m, this value is correspond a E(max).

By definition:

$k=\frac{2\pi}{\lambda}$

$k=8.98*10^{6} [rad/m]$

And the relation between λ and f is:

$c=\lambda f$

$f=\frac{c}{\lambda}$

$f=\frac{3*10^{8}}{700*10^{-9}}$

$f=4.28*10^{14}$

The angular frequency equation is:

$\omega=2\pi f$

$\omega=2\pi*4.28*10^{14}$

$\omega=2.69*10^{15} [rad/s]$

Therefore, the E equation, suing (1), will be:

$E=3.5(8.98*10^{6}x-2.69*10^{15}t)$ (2)

For the magnetic field we have the next equation:

$B=B_{max}(kx-\omega t)$ (3)

It is the same as E. Here we just need to find B(max).

We can use this equation:

$E_{max}=cB_{max}$

$B_{max}=\frac{E_{max}}{c}=\frac{3.5}{3*10^{8}}$

$B_{max}=1.17*10^{-8}T$

Putting this in (3), finally we will have:

$B=1.17*10^{-8}(8.98*10^{6}x-2.69*10^{15}t)$ (4)

I hope it helps you!

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3 years ago

A 90. 0-kg ice hockey player hits a 0. 150-kg puck, giving the puck a velocity of 45. 0 m/s. If both are initially at rest and i

Mice21 [21]

The distance traveled by the hockey player is 0.025 m.

<h3>The principle of conservation of linear momentum;</h3>

The principle of conservation of linear momentum states that, the total momentum of an isolated system is always conserved.

The final velocity of the hockey play is calculated by applying the principle of conservation of linear momentum;

$m_1v_1 = m_2 v_2\\\\v_1 = \frac{m_2 v_2}{m_1} \\\\v_1 = \frac{0.150 \times 45}{90} \\\\v_1 = 0.075 \ m/s$

The time taken for the puck to reach 15 m is calculated as follows;

$t = \frac{d}{v} \\\\t = \frac{15\ m}{45 \ m/s} \\\\t = 0.33 \ s$

The distance traveled by the hockey player at the calculated time is;

$d = vt\\\\d = 0.075 \ m/s \ \times 0.33 \ s\\\\d = 0.025 \ m$

Learn more about conservation of linear momentum here: brainly.com/question/7538238

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1 year ago