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3 years ago

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A baseball is thrown from the outfield toward the catcher. When the ball reaches its highest point, which statement is true? (A)

Its velocity is not zero, but its acceleration is zero. (B) Its velocity and its acceleration are both zero. (C) Its velocity is perpendicular to its acceleration. (D) Its acceleration depends on the angle at which the ball was thrown. (E) None of the above statements are true.

1 answer:

11111nata11111 [884]3 years ago

5 0

Answer:

C. Its velocity is perpendicular to its acceleration

Explanation:

Because acceleration is always perpendicular to the velocity when the velocity will change direction without change it's magnitude

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The electric field on the surface of an irregularly shaped conductor varies from 74.0 kN/C to 14.0 kN/C.

mrs_skeptik [129]

Answer:

(a). The local surface charge density at the point on the surface where the radius of curvature of the surface is greatest is 123.9 nC/m².

(b). The local surface charge density at the point on the surface where the radius of curvature of the surface is greatest is 654.9 nC/m².

Explanation:

Given that,

Electric field $E_{1}=74.0\ kN/C$

Electric field $E_{2}=14.0\ kN/C$

When the radius of curvature is greatest, the electric field at the surface will be smaller.

Where the radius of curvature is greatest

(a). We need to calculate the local surface charge density at the point on the surface

Using formula of charge density

$\sigma=\epsilon_{0}E_{2}$

Put the value into the formula

$\sigma=8.85\times10^{-12}\times14\times10^{3}$

$\sigma=1.239\times10^{-7}\ C/m^2$

$\sigma=123.9\times10^{-9}\ C/m^2$

$\sigma=123.9\ nC/m^2$

The local surface charge density at the point on the surface where the radius of curvature of the surface is greatest is 123.9 nC/m².

(b). We need to calculate the local surface charge density at the point on the surface where the radius of curvature of the surface is smallest

Using formula of charge density

$\sigma=\epsilon_{0}E_{1}$

Put the value into the formula

$\sigma=8.85\times10^{-12}\times74\times10^{3}$

$\sigma=6.549\times10^{-7}\ C/m^2$

$\sigma=654.9\times10^{-9}\ C/m^2$

$\sigma=654.9\ nC/m^2$

The local surface charge density at the point on the surface where the radius of curvature of the surface is greatest is 654.9 nC/m².

Hence, (a). The local surface charge density at the point on the surface where the radius of curvature of the surface is greatest is 123.9 nC/m².

(b). The local surface charge density at the point on the surface where the radius of curvature of the surface is greatest is 654.9 nC/m².

7 0

3 years ago

The freezer compartment in a conventional refrigerator can be modeled as a rectangular cavity 0.3 m high and 0.25 m wide with a

Anon25 [30]

Answer:

Thickness of Styrofoam insulation is 0.02741 m.

Explanation:

Given that,

Height = 0.25 m

Depth = 0.5 m

Power = 400 W

Temperature = 33°C

We need to calculate the area of Styrofoam

Using formula of area

$A=2(lb+bh+hl)$

Put the value into the formula

$A=2(0.3\times0.5+0.25\times0.5+0.5\times0.3)$

$A=0.85\ m^2$

Inner surface temperature of freezer

$T_{i}=-10°C=263\ K$

Outer surface temperature of freezer

$T_{o}=33+273=306\ K$

We need to calculate the thickness of Styrofoam insulation

Using Fourier law,

$q=\dfrac{kA}{L}(T_{o}-T_{i})$

$L=\dfrac{kA}{q}(T_{o}-T_{i})$

Put the value into the formula

$L=\dfrac{0.30\times0.85}{400}(306-263)$

$L=0.02741\ m$

Hence, Thickness of Styrofoam insulation is 0.02741 m.

8 0

3 years ago

The droplets on a glass of ice water are a result of water vapor releasing energy and changing to water droplets.

olya-2409 [2.1K]

Answer:

B. condensation

Explanation:

hope this helps

4 0

3 years ago

Read 2 more answers

Some springs are wound with the wire under torsion, so that they are naturally tightly compressed. The plot of extension vs. app

ANEK [815]

The "unstretched length" is shorter than the actual unloaded length because the load applied to the material caused the extension of the material thereby increasing its length.

<h3>Hooke's law</h3>

Hooke's law states that the force applied to an elastic material is directly proportional to the extension of the elastic material.

F = kx

where;

F is the applied force
k is the spring constant
x is the extension

Thus, we can conclude that, the "unstretched length" is shorter than the actual unloaded length because the load applied to the material caused extension of the material thereby increasing the length of the material.

Learn more about Hooke's law here: brainly.com/question/2648431

6 0

2 years ago

How many newtons of force will 2 pieces of paper have if one has a charge of .2 Coilombs and the other has a charge of .3 Coulom

sdas [7]

1) The electrostatic force between the two pieces of paper is $2.16\cdot 10^{13} N$

2)

If the charges of the two pieces of paper are both + or both -, they repel each other
If the charges of one piece of paper is positive and the other one is negative, they attract each other

Explanation:

1)

The electrostatic force between two charged objects is given by Coulomb's law:

$F=k\frac{q_1 q_2}{r^2}$

where:

$k=8.99\cdot 10^9 Nm^{-2}C^{-2}$ is the Coulomb's constant

$q_1, q_2$ are the two charges

r is the separation between the two charges

In this problem, we have the following situation:

$q_1 = 0.2 C$ is the charge on the first piece of paper

$q_2 = 0.3 C$ is the charge on the second piece of paper

$r=0.005 m$ is their separation

Substituting into the equation, we find the magnitude of the electrostatic force between them:

$F=k\frac{q_1 q_2}{r^2}=(8.99\cdot 10^9) \frac{(0.2)(0.3)}{(0.005)^2}=2.16\cdot 10^{13} N$

2)

The electrostatic force can be either attractive of repulsive, depending on the relative sign of the charges of the objects involved.

In particular, we have:

If the two charges have same sign (both positive or both negative), the force between them is repulsive
If the two charges have opposite sign (one positive and one negative), the force between them is attractive

Therefore, in this case:

If the charges of the two pieces of paper are both + or both -, they repel each other
If the charges of one piece of paper is positive and the other one is negative, they attract each other

Learn more about electric force:

brainly.com/question/8960054

brainly.com/question/4273177

#LearnwithBrainly

7 0

4 years ago