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2 years ago

Russ makes the diagram below to organize his notes about how Newton’s first law describes objects at equilibrium.

Physics

2 answers:

viva [34]2 years ago

8 0

Correct options:

Has a net force of zero

Explanation:

Newton's first law, also known as law of inertia, states that:

"An object at rest which has a net force of zero acting on it stays at rest, and an object moving at constant velocity which has a net force of zero acting on it continues its motion at constant velocity"

The first situation (object at rest) is called static equilibrium, while the second situation (object moving at constant velocity) is called dynamic equilibrium. As we read from the statement of the Newton's first law, in both situations the object has a net force of zero acting on it, so this is the label that should be placed in region X (which is the region in common between both dynamic and static equilibrium)

tiny-mole [99]2 years ago

6 0

Newton's first law states that an object at rest remains so until acted upon by external forces or an object in motion does so without accelerating (that is, at constant speed).

Therefore, x can only describe an object coming to rest. That, the last option is more correct.

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A solenoid with 3,000.0 turns is 70.0 cm long. If its self-inductance is 25.0 mH, what is its radius? (The value of μ0 is 4π x 1

nevsk [136]

Answer:

A. 2.2*10^-2m

Explanation:

Using

Area = length x L/ uo xN²

So A = 0.7m * 25 x 10^-3H /( 4π x10^-7*

3000²)

A = 17.5*10^-3/ 1.13*10^-5

= 15.5*10^-2m²

Area= π r ²

15.5E-2/3.142 = r²

2.2*10^2m

Explanation:

5 0

2 years ago

B⃗ is kept constant but the coil is rotated so that the magnetic field, B⃗ , is now in the plane of the coil. How will the magne

s344n2d4d5 [400]

Answer:

The flux decreases because the angle between B⃗ and the coil's axis changes.

Explanation:

The flux through the coil is given by a dot product, between the magnetic field and the vector representing the area of the coil.

$\Phi = \vec{B}\cdot \vec{S} = BScos(\theta)$

The latter vector has direction perpendicular to the plane in which the area of the coil is, and magnitude equal to the area of the coil. As in the attached image, the vector S is the vector respresenting the area of the coil.

Therefore, the flux will be maximum when the vector S is in the same direction as B, and will be zero when they are perpendicular.

Now, if the coil is rotated so that the magnetic field is in the plane of the coil then, the vectors S and B are perpendicualr, and there will not be net magnetic flux, that is, the flux will decrease.

3 0

2 years ago

Read 2 more answers

An archer tests various arrowheads by shooting arrows at a pumpkin that is suspended from a tree branch by a rope, as shown to t

erik [133]

Answer:

Bounce 1 , pass 3, emb2

Explanation:

(By the way I am also doing that question on College board physics page) For the Bounce arrow, since it bumps into the object and goes back, it means now it has a negative momentum, which means a larger momentum is given to the object. P=mv, so the velocity is larger for the object, and larger velocity means a larger kinetic energy which would result in a larger change in the potential energy. Since K=0.5mv^2=U=mgh, a larger potential energy would have a larger change in height which means it has a larger angle θ with the vertical line. Comparing with the "pass arrow" and the "Embedded arrow", the embedded arrow gives the object a larger momentum, Pi=Pf (mv=(M+m)V), it gives all its original momentum to the two objects right now. (Arrow and the pumpkin), it would have a larger velocity. However for the pass arrow, it only gives partial of its original momentum and keeps some of them for the arrow to move, which means the pumpkin has less momentum, means less velocity, and less kinetic energy transferred into the potential energy, and means less change in height, less θangle. So it is Bounce1, pass3, emb2.

6 0

2 years ago

(8%) Problem 9: Helium is a very important element for both industrial and research applications. In its gas form it can be used

exis [7]

Answer:

2046.37 kPa

Explanation:

Given:

Number of moles, n = 125

Temperature, T = 20° C = 20 + 273 = 293 K

Radius of the cylinder, r = 17 cm = 0.17 m

Height of the cylinder, h = 1.64 m

thus,

volume of the cylinder, V = πr²h

= π × 0.17² × 1.64

= 0.148 m³

Now,

From the ideal gas law

we have

PV = nRT

here,

P is the pressure

R is the ideal gas constant = 8.314 J / mol. K

thus,

P × 0.148 = 125 × 8.314 × 293

P × 0.148 = 304500.25

P = 2046372.64 Pa = 2046.37 kPa

6 0

2 years ago

A street light is mounted at the top of a 15-ft-tall pole. A man 6 ft tall walks away from the pole with a speed of 4 ft/s along

babymother [125]

Answer:

Explanation:

height of pole = 15 ft

height of man = 6 ft

Let the length of shadow is y .

According to the diagram

Let at any time the distance of man is x.

The two triangles are similar

$\frac{y-x}{y}=\frac{6}{15}$

15 y - 15 x = 6 y

9 y = 15 x

$y=\frac{5}{3}x$

Differentiate with respect to time.

$\frac{dy}{dt}=\frac{5}{3}\frac{dx}{dt}$

As given, dx/dt = 4 ft/s

$\frac{dy}{dt}=\frac{5}{3}\times 4$

$\frac{dy}{dt}=\frac{20}{3}$ ft/s

6 0

2 years ago