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2 years ago

A car travels between two towns 80 miles apart in 2 hours. What is its average speed?

2 answers:

7 0

Speed is defined as the distance per unit time.
So we can calculate the speed by :

S = Distance traveled/Time taken
S = 80 /2
S = 40 miles/hour

iren [92.7K]2 years ago

6 0

Answer:

Average speed of the car is 40 miles per hour

Explanation:

It is given that,

Distance covered by the car, d = 80 miles

Time taken by the car, t = 2 hours

We need to find the average speed of the car. It is given by :

$v=\dfrac{d}{t}$

$v=\dfrac{80\ miles}{2\ h}$

v = 40 miles/hour

So, the average speed of the car is 40 miles per hour. Hence, this is the required solution.

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What is the name of the line drawn perpendicular to the surface where a light ray strikes?

AnnyKZ [126]

It is the normal line

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2 years ago

Find the ratio of the diameter of iron to copper wire, if they have the same resistance per unit length (as they might in househ

Natasha_Volkova [10]

Answer:

The ratio of the diameter of iron to Cu is;

$\frac{d{Fe} }{ d{Cu} } =\sqrt{\frac{p_{Fe} }{ p_{Cu} }}$

Explanation:

R=(ρL)/A

R is resistance,
L is length,
A is area,
ρ is resistivity
d is diameter

from the question the two materials have the same resistance per unit length.

$\frac{R}{L}= \frac{p}{A}$

$\frac{R}{L}$ for iron = $\frac{R}{L}$ for copper

This means we can equate ρ/A for both materials.

$\frac{p_{Fe} }{A_{Fe} } =\frac{p_{Cu} }{A_{Cu} }$

re-arranging the equation we have,

$\frac{A_{Fe}}{A_{Cu} } =\frac{p_{Fe} }{ p_{Cu} }$

$A=\pi \frac{d^{2} }{4}$

$\frac{A_{Fe}}{A_{Cu} } =\frac{d^{2}{Fe} }{ d^{2}{Cu} }$

$\frac{d^{2}{Fe} }{ d^{2}{Cu} } =\frac{p_{Fe} }{ p_{Cu} }$

$\frac{d{Fe} }{ d{Cu} } =\sqrt{\frac{p_{Fe} }{ p_{Cu} }}$

5 0

3 years ago

A. Write two or three sentences to describe the conductivity of an insulator. Explain its conductivity in terms of the electrons

aliya0001 [1]

PART A)

Conductivity of insulator is very small as there is no free electrons to conduct the current trough that medium

So here number of conduction electrons are very less in insulators

PART B)

Resistance is the property of a conducting medium which will oppose the flow of current trough it

Resistance of wire directly depends on its length so resistance of long wire will be more than the resistance of short wire

Resistance inversely depends on the area so if a wire has more crossectional area then its resistance must be small

PART C)

power of light bulb is defined as rate of electrical energy

it is given by formula

P = i V

here we know that

i = 1.46 A

V = 120 volts

so power is given as

$P = 1.46 \times 120$

$P = 175.2 Watt$

3 0

2 years ago

Read 2 more answers

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madreJ [45]

The answer is B. Vas deferens.

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4 0

3 years ago

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A child in a tree house uses a rope attached to a basket to lift a 24 N dog upward through a distance of 4.9 m into the house.

jenyasd209 [6]

<h3>Answer:</h3>

117.6 Joules

<h3>Explanation:</h3>

<u>We are given;</u>

Force of the dog is 24 N
Distance upward is 4.9 m

We are required to calculate the work done

Work done is the product of force and distance
That is; Work done = Force × distance
It is measured in Joules.

In this case;

Force applied is equivalent to the weight of the dog.

Work done = 24 N × 4.9 m

= 117.6 Joules

Hence, the work done in lifting the dog is 117.6 Joules

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3 years ago