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3 years ago

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How long does it take the Sun to melt a block of ice at 0∘C with a flat horizontal area 1.0 m2 and thickness 2.0 cm ? Assume tha

t the Sun's rays make an angle of 30 ∘ with the vertical and that the emissivity of ice is 0.050.

1 answer:

Savatey [412]3 years ago

4 0

The answer is c don't ask why it just is

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Write the electron configurations for titanium (Ti), vanadium (V), chromium (Cr), and manganese (Mn).

Tomtit [17]

See from periodic table the proton or atomic number of elements u want to know about then as u know first electron shell can hold 2 electrons 2nd can hold eight as well as all others........protons are equal to electrons so divide proton number into shells but remember to use amounts which it can hold

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3 years ago

What information does the period number give about an atom?

Anton [14]

Answer:All of the elements in a period have the same number of atomic orbitals. For example, every element in the top row (the first period) has one orbital for its electrons. All of the elements in the second row (the second period) have two orbitals for their electrons.Explanation:

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3 years ago

Read 2 more answers

A ball thrown horizontally from a point 30.0 m above the ground strikes the ground after travelling a horizontal distance of 18.

AURORKA [14]

The components of the ball's position $r$ at time $t$ are

$\begin{cases}r_x(t)=v_{0x}t\\v_y(t)=30.0-4.9t^2\end{cases}$

The ball stops 18.0 m from where it began, so that

$\begin{cases}18.0=v_{0x}t\\0=30.0-4.9t^2\end{cases}$

From the second equation, we can show that the ball travels for about $t=2.47$ seconds, which means it was initially thrown with a horizontal velocity of

$18.0\,\mathrm m=v_{0x}(2.47\,\mathrm s)\implies v_{0x}=7.29\,\dfrac{\mathrm m}{\mathrm s}$

7 0

4 years ago

A 2-kg wood block is pulled by a string across a rough horizontal floor. The string exerts a tension force of 30 N on the block

Luden [163]

Answer:

Work done, W = 84.57 Joules

Explanation:

It is given that,

Mass of the wooden block, m = 2 kg

Tension force acting on the string, F = 30 N

Angle made by the block with the horizontal, $\theta=20^{\circ}$

Distance covered by the block, d = 3 m

Let W is the work done by the tension force. It can be calculated as :

$W=F\ cos\theta\times d$

$W=30\times cos(20)\times 3$

W = 84.57 Joules

So, the work done by the tension force is 84.57 Joules. Hence, this is the required solution.

7 0

3 years ago

An 1120 kg car traveling at 17.2 m/s is brought to a stop while skidding 40m. Calculate the work done on the car by the friction

Nesterboy [21]

Answer:

Work = 165670.4 J = 165.67 KJ

Explanation:

First, we will find the deceleration of the car, using the 3rd equation of motion:

$2as = v_{f}^2 - v_{i}^2\\$

where,

a = deceleration = ?

s = skid distance = 40 m

vf = final speed = 0 m/s

vi = initial speed = 17.2 m/s

Therefore,

$2a(40\ m) = (0\ m/s)^2 - (17.2\ m/s)^2\\a = - 3.698\ m/s^2$

the negative sign indicates deceleration here.

Now, we will calculate the braking force applied by the brakes on the car:

$F = ma\\F = (1120\ kg)(-3.698\ m/s^2)\\F = - 4141.76\ N$

the negative sign indicates braking force.

Now, we will calculate the work done using the magnitude of this force:

$Work = |F|s\\Work = (4141.76\ N)(40\ m)\\$

<u>Work = 165670.4 J = 165.67 KJ</u>

8 0

3 years ago