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3 years ago

In an electric motor, periodically changing the electromagnet can cause the axle to spin because

2 answers:

5 0

We want to know why does the axle spin in the electric motor. When we periodically change the electromagnet via alternate current, the magnetic field reverses directions which creates a force on the axle and so the axle starts spinning. So the correct answer is d. the magnetic field reverses direction.

amm18123 years ago

4 0

The answers are,

B
B
D
D

Hope I helped!

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A 1.25-kg ball begins rolling from rest with constant angular acceleration down a hill. If it takes 3.60 s for it to make the fi

miv72 [106K]

Answer:

The time taken is $\Delta t = 1.5 \ s$

Explanation:

From the question we are told that

The mass of the ball is $m = 1.25 \ kg$

The time taken to make the first complete revolution is t= 3.60 s

The displacement of the first complete revolution is $\theta = 1 rev = 2 \pi \ radian$

Generally the displacement for one complete revolution is mathematically represented as

$\theta = w_i t + \frac{1}{2} * \alpha * t^2$

Now given that the stone started from rest $w_i = 0 \ rad / s$

$2 \pi =0 + 0.5* \alpha *(3.60)^2$

$\alpha = 0.9698 \ s$

Now the displacement for two complete revolution is

$\theta_2 = 2 * 2\pi$

$\theta_2 = 4\pi$

Generally the displacement for two complete revolution is mathematically represented as

$4 \pi = 0 + 0.5 * 0.9698 * t^2$

=> $t^2 = 25.9187$

=> $t= 5.1 \ s$

The time taken to complete the next oscillation is mathematically evaluated as

$\Delta t = t_2 - t$

substituting values

$\Delta t = 5.1 - 3.60$

$\Delta t = 1.5 \ s$

7 0

3 years ago

Which statement accurately explains why the kinetic energy of the first rider is greater?

Dvinal [7]

Hey

The formula of kinetic energy is 1/2mv^2

So it depends on mass and velocity

As mass increases , kinetic energy increase .

So option b , the first rider had more mass is correct z

5 0

2 years ago

Read 2 more answers

What is a electron orbit?

Advocard [28]

the path of an electron around the nucleus of an atom

5 0

3 years ago

Read 2 more answers

The drag force pushes opposite your motion as you ride a bicycle. If you double your speed, what happens to the drag force?

timurjin [86]

Answer: The drag force goes up by a factor of 4

Explanation:

The Drag Force equation is:

$F_{D}=\frac{1}{2}C_{D}\rho A_{D}V^{2}$ (1)

Where:

$F_{D}$ is the Drag Force

$C_{D}$ is the Drag coefficient, which depends on the material

$\rho$ is the density of the fluid where the bicycle is moving (air in this case)

$A_{D}$ is the transversal area of the body or object

$V$ the bicycle's velocity

Now, if we assume $C_{D}$ , $\rho$ and $A_{D}$ do not change, we can rewrite (1) as:

$F_{D}=C.V^{2}$ (2)

Where $C$ groups all these coefficients.

So, if we have a new velocity $V_{n}$ , which is the double of the former velocity:

$V_{n}=2V$ (3)

Equation (2) is written as:

$F_{D}=C.V_{n}^{2}=C.(2V)^{2}$

$F_{D}=4CV^{2}$ (4)

Comparing (2) and (4) we can conclude the Drag force is four times greater when the speed is doubled.

7 0

3 years ago

It takes 5.0 seconds for a wave with a wavelength of 2.5 m to travel past your location. What’s the period of the wave. What is

Anna35 [415]

(a) Period of the wave
The period of a wave is the time needed for a complete cycle of the wave to pass through a certain point.
So, if an entire cycle of the wave passes through the given location in 5.0 seconds, this means that the period is equal to 5.0 s: T=5.0 s.

(b) Frequency of the wave
The frequency of a wave is defined as
$f= \frac{1}{T}$
since in our problem the period is $T=5.0 s$ , the frequency is
$f= \frac{1}{5.0 s}=0.2 Hz$

(c) Speed of the wave
The speed of a wave is given by the following relationship between frequency f and wavelength $\lambda$ :
$v=f \lambda = (0.2 Hz)(2.5 m)=0.5 m/s$

8 0

3 years ago