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3 years ago

10

Which of these offers the least resistance to electrical current flow? A. a battery B. copper wire C. a 60-Watt light bulb D. a

100-Watt light bulb

1 answer:

ehidna [41]3 years ago

4 0

From the things on that list, the copper wire has the least resistance ... unless it happens to be several miles long.

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In the autocollimation experiment of Sec. 3.5, a thin convex lens is placed 25 cm from a pinhole that acts as a point source of

Lera25 [3.4K]

Answer:

25 cm

Explanation:

Since, in the question it is given that the final image after reflection through the convex lens and then the reflection by the plane mirror is formed at the pinhole itself.

This means that the pinhole must be at the focus of the convex lens, such that the lens makes the ray perpendicular to the mirror and hence focal length of the lens = 25 cm.

4 0

4 years ago

A small block is attached to an ideal spring and is moving in SHM on a horizontal, frictionless surface. The amplitude of the mo

makvit [3.9K]

Answer:

a = -0.59 m/s^2

v = 0.22 m/s

Explanation:

The equation of motion in simple harmonic motion is defined as

$x(t) = A\cos(\omega t - \phi)$

where A is the amplitude, ω is the angular frequency, and Ф is the phase angle which has to be determined by initial conditions.

The period of the motion is given, so the angular frequency could be calculated.

$\omega = 2\pi f = 2\pi \frac{1}{T} = 2*3.14*(1/3.28) = 1.91$

The initial conditions are not given in the question, so I will assume that at t = 0, the block is at the origin (x = 0). (This assumption will not affect our final result, we can as well choose another initial point.)

$x(t=0) = 0 = 0.2\cos(1.91*0 - \phi)\\\cos(\phi) = 0\\\phi = \pi/2$

Let’s find the time when x = 0.160 m.

$0.16 = 0.2\cos(1.91t - \pi/2)\\1.91t - \pi/2 = 0.6435\\1.91t = 0.6435 + 1.5708 = 2.2143\\t = 1.15~s$

The velocity function is the derivative of the position function with respect to time.

$v(t) = \frac{dx(t)}{dt} = -\omega A\sin(\omega t - \phi)$

Similarly, the acceleration function is the derivative of velocity function with respect to time.

$a(t) = -\omega^2A\cos(\omega t - \phi)$

A) $a(t = 1.15) = -(1.91)^2 0.2 \cos(1.91*1.15 - \pi/2) = -0.59~m/s^2$

B) $v(t = 1.51) = 1.91*0.2\sin(1.91*1.15 - \pi/2) = 0.22~m/s$

3 0

3 years ago

When you move from place to place, how do you know you moved ?

Nastasia [14]

If Your Somewhere Different .

7 0

3 years ago

Read through the and calculate the predicted change in kinetic energy of the oblect compared to 50 kg ball traveling at 10 m/s .

Sliva [168]

Answer:

A 50 kg ball traveling at 20 m/s would have 4 times more kinetic energy.

A 50 kg ball traveling at 5 m/s would have 4 times less kinetic energy.

A 50 kg person falling at 10 m/s would have the same kinetic energy.

Explanation:

hope this helps:)

5 0

3 years ago

A laser beam is incident on two slits with a separation of 0.230 mm, and a screen is placed 4.75 m from the slits. If the bright

Mariulka [41]

Answer:

$7.55\times 10^{-7} m$

Explanation:

We are given that

d=0.23 mm= $0.23\times 10^{-3} m$

$1mm=10^{-3} m$

Screen is placed from the slits at distance ,L=4.75 m

The bright interference fringes on the screen are separated by 1.56 cm.

$\Delta y=1.56 cm=1.56\times 10^{-2} m$

1 m=100 cm

We have to find the wavelength of laser light.

We know that

$\Delta y=\frac{\lambda L}{d}$

Substitute the values

$1.56\times 10^{-2}=\frac{\lambda\times 4.75}{0.23\times 10^{-3}}$

$\lambda=\frac{1.56\times 10^{-2}\times 0.23\times 10^{-3}}{4.75}$

$\lambda=7.55\times 10^{-7} m$

4 0

3 years ago