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3 years ago

A 2-kg book falls off a shelf. it hits a student traveling 2 m/s. how much kinetic energy does the book have?

Physics

1 answer:

jekas [21]3 years ago

5 0

Kinetic energy = 1/2 * m * V^2

K = 1/2 * 2kg * 4

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A block of size 20m x 10 mx 5 m exerts a force of 30N. Calculate the

Orlov [11]

Answer:

We know that force applied per unit area is called pressure.

Pressure = Force/ Area

When force is constant than pressure is inversely proportional to area.

1- Calculating the area of three face:

A1 = 20m x 10 m =200 Square meter

A2 = 10 mx 5 m = 50 Square meter

A3 = 20m x 5 m = 100 Square meter

Therefore A1 is maximum and A2 is minimum.

2- Calculate pressure:

P = F/ A1 = 30 / 200 = 0.15 Nm⁻² ( minimum pressure)

P = F / A2 = 30 / 50 = 0.6 Nm⁻² ( maximum pressure)

Hence greater the area less will be the pressure and vice versa.

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3 years ago

How many mL are in a cubic centimeter?

Furkat [3]

None of the above. 1 mL= 1 cubic centimeter
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4 years ago

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A cube of water 10 cm on a side is placed in a microwave beam having Ea = 11 kV/m‘ The microwaves illuminate one faceofthe cube,

Shtirlitz [24]

Answer:

The time is 133.5 sec.

Explanation:

Given that,

One side of cube = 10 cm

Intensity of electric field = 11 kV/m

Suppose How long will it take to raise the water temperature by 41°C Assume that the water has no heat loss during this time.

We need to calculate the rate of energy transfer from the beam to the cube

Using formula of rate of energy

$P=(0.80)IA$

$P=0.80\times\dfrac{c\mu_{0}E^2}{2}\times A$

Put the value into the formula

$P=0.80\times\dfrac{3\times10^{8}\times8.85\times10^{-12}\times(1.1\times10^{4})^2}{2}\times(10\times10^{-2})^2$

$P=1285.02\ W$

We need to calculate the amount of heat

Using formula of heat

$E =mc\Delta T$

$E =\rho Vc\Delta T$

Put the value into the formula

$E=1000\times(0.10)^3\times4186\times41$

$E=171626\ J$

We need to calculate the time

Using formula of time

$t=\dfrac{E}{P}$

Put the value into the formula

$t=\dfrac{171626}{1285.02}$

$t=133.5\ sec$

Hence, The time is 133.5 sec.

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4 years ago

How will the solubility of a gas solute change if the pressure above the solution is reduced?

Hoochie [10]

If the pressure above a solution containing a gas solute is reduced, the limit of the gas's solubility will decrease.

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4 years ago

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How can a cyclist minimize friction as he or she rides? A. by increasing the weight of the bike B. by increasing the tread on hi

jek_recluse [69]

B I believe is the answer!

Hope this helps and have a great day!!!

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3 years ago

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