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3 years ago

To raise an arm upward, the muscle on one side of it contracts. What happens to the muscle on the opposite side of the arm?

Physics

2 answers:

s2008m [1.1K]3 years ago

6 0

Answer:

it relaxes B

Explanation:

enyata [817]3 years ago

5 0

Answer:

It relaxes

Explanation:

I took the test I hope it helps

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To transform electrical energy into mechanical energy, the electromagnet in a

lidiya [134]

Answer:

Motors commonly contain a "commutator" which allows a magnetic field due to a loop of wire to always be in a say "clockwise or counterclockwise" direction even tho the loop of wire is rotating.

That means that magnetic field due to the surrounding magnets is always in the same direction, but the magnetic field due to the rotating loop of wire is continually changing so that it will always oppose the surrounding field which remains in a constant direction.

This is most easily seen in a "DC - direct current motor".

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2 years ago

Which is not a way to accelerate an object?

GREYUIT [131]

<span>Slowing an object down is not a means of accelerating it. It actually decelerates the motion of an object. Speeding it up, changing its direction and applying balanced forces accelerate an object. In order for an object to accelerate, a force must be applied. It follows Newton’s second law of motion where it states that a body at rest remains at rest unless a force is acted upon it. When you move an object, you are exerting a force onto it. By exerting a force on the object, you are actually displacing it from its initial position. You cannot apply force to the object without altering its position. Keep in mind that when you exert work, you are exerting energy too. </span>

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3 years ago

A certain ocean wave has a frequency of 0.07 hertz and a wavelength of 10 meters. what is the wave's speed? a 0.07 m/s

Elis [28]

V=f*wavelength
v=0.07hz*10m
v=0.7 m/s

8 0

3 years ago

I will be so thankful if u answer correctly!!

polet [3.4K]

Explanation:

The acceleration due to gravity on earth $g_{E}$ is given by

$g_{E} = G\dfrac{M_{E}}{R_{E}^{2}}$

where $G$ = universal gravitational constant

$\:\:\:\:\:\:\:\:\:\:\:\:M_{R}$ = mass of the earth

$\:\:\:\:\:\:\:\:\:\:\:\:R_{E}$ = radius of the earth

Planet Krypton has twice the mass of earth and 3 times the radius so its acceleration due to gravity $g_{K}$ is

$g_{K} = G\dfrac{M_{K}}{R_{K}^{2}}$

$\:\:\:\:\:\: = G\dfrac{(2M_{E})}{(3R_{E})^{2}}$

$\:\:\:\:\;\:= (\dfrac{2}{9})G\dfrac{M_{E}}{R_{E}^{2}}$

$g_{K} = (\dfrac{2}{9})\:g_{E}$

If we multiply both sides by Superman's mass, we get his weights on both planets:

$mg_{K} = (\dfrac{2}{9})\:(mg_{E})$

$W_{K} = (\dfrac{2}{9})\:W_{E} = (\dfrac{2}{9})(900\:N)= 200\:N$

3 0

3 years ago

A box has a weight of 150 N and is being pulled across a horizontal floor by a force that has a magnitude of 110 N. The pulling

ivann1987 [24]

Answer:

42.99°

Explanation:

$F_h$ = Kinetic friction force

$F_{\theta}$ = Pulling force at angle $\theta$

$N_h$ = Weight of the box = 150 N

Kinetic friction force

$F_h=\muN_h$

Pulling force at angle $\theta$

$F_{\theta}=\muN_{\theta}$

N = Pulling force

According to question

$\frac{F_h}{F_{\theta}}=\frac{2}{1}\\\Rightarrow \frac{\muN_h}{\muN_{\theta}}=2\\\Rightarrow \frac{N_h}{N_{\theta}}=2\\\Rightarrow N_{\theta}=\frac{N_h}{2}\\\Rightarrow N_{\theta}=\frac{150}{2}\\\Rightarrow N_{\theta}=75\ N$

Applying Newton's second law in the vertical direction we get

$N_h-Nsin\theta=N_{\theta}\\\Rightarrow 150-110sin\theta=75\\\Rightarrow \theta=sin^{-1}\frac{75}{110}\\\Rightarrow \theta=42.99\ ^{\circ}$

The angle is 42.99°

8 0

3 years ago