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pishuonlain [190]

2 years ago

10

A wire oriented so that the current flows into the screen experiences a force that deflects downward. The direction of the magne

tic field must be
a. left.
b. right.
c. down.
d. up.

1 answer:

jasenka [17]2 years ago

7 0

Answer:b-right

Explanation:

Given

current is flowing into the screen i.e. $-\hat{k}$ direction

length of wire is also in $-\hat{k}$ direction

Force experienced is in negative y direction i.e. $-\hat{j}$

Force experienced by a current carrying wire in a magnetic field experience a force is given by

$F=I\left ( \vec{L}\times \vec{B}\right )$

where I=current

L=length of element

B=magnetic field

Direction of magnetic field must be in $\hat{i}$

as $-\hat{k}\times \hat{i}=-\hat{j}$

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Answer:

θ = 13.7º

Explanation:

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The external forces capable to do work on the combination of child +sled, are the friction force (opposing to the displacement), and the component of the weight parallel to the slide.
As this last work is just equal to the change in the gravitational potential energy (with opposite sign) , we can write the following equation:

$\Delta K + \Delta U = W_{nc} (1)$

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ΔU, is the change in the gravitational potential energy.
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$\Delta U = 0 - m*g*h = -m*g*d* sin\theta (3)$

Finally, the work done for non-conservative forces, is the work done by the friction force, along the slope, as follows:

$W_{nc} = F_{f} * d * cos 180\º \\\\ = 0.2*m*g*d* cos 180\º = -0.2*m*g*d (4)$

Replacing (2), (3), and (4) in (1), simplifying common terms, and rearranging, we have:

$\frac{1}{2}* (v_{f} ^{2} - v_{0} ^{2}) = g*d* sin\theta -0.2*g*d$

Replacing by the givens and the knowns, we can solve for sin θ, as follows: $\frac{1}{2}*( (4.30 m/s) ^{2} - (0.75 m/s)^{2}) = 9.8 m/s2*25.5m* sin\theta -0.2*9.8m/s2*25.5m\\ \\ 8.56 (m/s)2 = 250(m/s)2* sin \theta -50 (m/s)2\\ \\ sin \theta = \frac{58.6 (m/s)2}{250 (m/s)2} = 0.236$ ⇒ θ = sin⁻¹ (0.236) = 13.7º

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3 years ago

An object moves from point A to B to C to D and finally to A

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here's the solution,

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So, Circumference :

=》

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=》

$2 \times 3.14 \times 3$

=》

$18.84$

(a). Distance covered by moving object is 18.84 km

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3 years ago