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4 years ago

When objects are heated they tend to expand because

1 answer:

5 0

Hello!
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When objects are heated, their molecules tend to vibrate fast. As they vibrate, the space between each atom increases. This keeps on happening, and the object expands until it has cooled down.
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Hope this helps! :)

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Which of the following activities works on muscle strength? A. cutting hedges B. moving furniture C. raking leaves D. vacuuming

Ksenya-84 [330]

The answer would be B

3 0

3 years ago

An electron moving with a velocity v⃗ = 5.0 × 107 m/s i^ enters a region of space where perpendicular electric and a magnetic fi

stiv31 [10]

Answer:

Magnetic field, $B=2\times 10^{-4}\ T$

Explanation:

Given that,

Velocity of electron, $v=5\times 10^7\ m/s$

It enters a region of space where perpendicular electric and a magnetic fields are present.

Magnitude of electric field, $E=10^4\ V/m$

We need to find the magnetic field will allow the electron to go through the region without being deflected.

Magnetic force on the electron, $F_m=qvB\ sin\theta$ .......(1)

Electric force on the electron, F = q E........(2)

From equation (1) and (2) we get:

$qvB\ sin\theta=qE$

$B=\dfrac{E}{v}$

$B=\dfrac{10^4\ V/m}{5\times 10^7\ m/s}$

B = 0.0002 T

$B=2\times 10^{-4}\ T$

Hence, this is the required solution.

3 0

3 years ago

A train travels 63 kilometers in 2 hours, and then 56 kilometers in 3 hours. What is its average speed? i need the answer and un

kolbaska11 [484]

The average speed is the ratio between the total space and the total time of the motion:
$v= \frac{S_{tot}}{t_{tot}}$
The total space is
$S_{tot}=63 km + 56 km = 119 km$
while the total time is
$t_{tot}=2h+3h = 5h$
So, the average velocity is
$v= \frac{119 km}{5 h} =23.8 km/h
$

We can also rewrite it in m/s. The total space is $S_{tot}=119000 m$ , while the time is $t_{tot}=5h\cdot 3600 s/h = 18000s$ , and so
$v= \frac{119000m}{18000s}=6.6 m/s$

4 0

3 years ago

If the pressing force on the slidding surfaces is greater then friction will be

Tema [17]

Answer:

Kinetic friction is lesser than limiting friction. Two surfaces are rubbed together, first with a smaller force and then with a greater force.

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3 years ago

At a certain elevation, the ________ , the air becomes saturated and water-vapor molecules ________.

andriy [413]

At certain altitude, the temperature of air decrease, The air becomes saturated and water vapour molecules starts condensing.

As the altitude of air increase, the atmospheric pressure decrease due to which the temperature of the air decrease. The water molecules in the atmosphere start condensing, which saturate the air (that is air can no hold water molecules), due to which the water vapour molecules starts condensing and falls on the earth in the form of rain.

4 0

4 years ago