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Kamila [148]
3 years ago
13

A resistor is made by winding a very long thin metal wire, insulated so adjacent coils do not touch. At room temperature, the re

sistance is 100 ohms.
If the resistor is then cooled to 77 K, the resistance:

A. changes only slightly, if at all.
B. increases significantly (more than a factor of two).
C. decreases significantly (more than a factor of 1/2).
Physics
1 answer:
Vladimir79 [104]3 years ago
3 0

Answer:

Option A

Explanation:

The correct answer is  Option A.

At room temperature, the resistance is equal to 100 ohms.

When the temperature is reduced to 77 K from room temperature, change in the resistance is very less.

The temperature coefficient of the resistivity of most of the metal is small for the metals which are approximately equal  0.01 /K.

hence, Change is only slightly.

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dalvyx [7]

Answer:

46 m at 9.5 degrees east of south

Explanation:

5 0
3 years ago
Bryan Allen pedaled a human-powered aircraft across the English Channel from the cliffs of Dover to Cap Gris-Nez on June 12, 197
Leno4ka [110]

(a) 3.58 km 45° south of east

The total displacement is given by:

d=vt

where

v is the average velocity

t is the time

The average velocity is:

v = 3.53 m/s

While we need to convert the time from minutes to seconds:

t=169 min \cdot 60 s/min = 10140 s

Therefore, the magnitude of the displacement is

d=(3.53)(10140)=35794 m = 3.58 km

And the direction is the same as the velocity, therefore 45° south of east.

(b) 5.53 m/s 90° south of east

The velocity of the air relative to the ground is

v_a = 2.00 m/s

and the direction is exactly opposite to that of Allen, so it is 45° north of west. Allen's velocity relative to the ground is

v = 3.53 m/s

So this must be the resultant of Allen's velocity relative to the air (v') and the air's speed (v_a). Since these two vectors are in opposite direction, we have

v= v'-v_a

Therefore we find v', Allen's velocity relative to the air:

v'=v+v_a = 3.53 + 2.00 = 5.53 m/s

The direction must be measured relative to the air's reference frame. In this reference frame, Allen is moving exactly backward, so his direction will be 90° south of east.

(c) 56.1 km at 90° south of east.

Since Allen's velocity relative to the air is

v' = 5.53 m/s

Then the displacement of Allen relative to the air will be given by

d'=v't

and substituting,

d'=(5.53)(10140)=56074 m = 56.1 km

And the direction is the same as that of the velocity, therefore will be 90° south of east.

3 0
4 years ago
All else equal, the payback period for a project will decrease whenever the_______.
telo118 [61]

Answer:

(B) cash inflows are moved earlier in time.

Explanation:

The payback period stated time-frame during which the initial amount of investment should be recovered. It is expressed in the year form

The formula to compute the payback period is shown below:

Payback period = Initial investment ÷ Net cash flow

where,  

The net cash flow = annual net operating income + depreciation expenses

The payback period of the project decreases when the accumulated starting year cash flows increases that results the movement of the cash inflows earlier in time

3 0
3 years ago
Read 2 more answers
Can u plz help I'm failing and I have 2 weeks to get my grades up someone help me plz plz plz plz this is not a test ok it was h
Anastaziya [24]
1. B
2. A
3. B
4. C
5. heterogeneous
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8. true
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10. true
7 0
4 years ago
Read 2 more answers
Question 6
Margaret [11]

Limestone and dolomite are the rocks present in the locations which leads to the formation of caves.

<h2>Formation of caves</h2>

The type of rocks that once existed in these  locations are limestone and dolomite whereas the pH of the nearby groundwater is slightly acidic which is responsible for the formation of caves. Caves are formed by the dissolution of limestone due to acid rain.

<h3>Acid rain</h3>

Rainwater reacts with carbon dioxide from the air and percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone which become turn to form caves so we can conclude that Limestone and dolomite are the rocks present in the locations which leads to the formation of caves.

Learn more about caves here: brainly.com/question/7965722

Learn more: brainly.com/question/26111031

4 0
2 years ago
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