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3 years ago

Suppose a car approaches a hill and has an initial speed of

Physics

1 answer:

kvv77 [185]3 years ago

5 0

Answer:

a) 1.73*10^5 J

b) 3645 N

Explanation:

106 km/h = 106 * 1000/3600 = 29.4 m/s

If KE = PE, then

mgh = 1/2mv²

gh = 1/2v²

h = v²/2g

h = 29.4² / 2 * 9.81

h = 864.36 / 19.62

h = 44.06 m

Loss of energy = mgΔh

E = 780 * 9.81 * (44.06 - 21.5)

E = 7651.8 * 22.56

E = 172624.6 J

Thus, the amount if energy lost is 1.73*10^5 J

Work done = Force * distance

Force = work done / distance

Force = 172624.6 / (21.5/sin27°)

Force = 172624.6 / 47.36

Force = 3645 N

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An electric motor consumes 8.40 kJ of electrical energy in 1.00 min. Part A If one-third of this energy goes into heat and other

Salsk061 [2.6K]

Answer:

The torque is 0.31 Nm.

Explanation:

Electrical energy, E = 8400 J

time, t = 1 min

Angular speed, w = 2900 rpm = 303.53 rad/s

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The toque is given by

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3 years ago

A piece of candy has 5 calories (or 5000 calories). if it could be burned, leaving nothing but carbon dioxide and water, how muc

posledela

A) 500 calories
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3 years ago

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LINK THE WORDS TO THE UNDERLINE. The 4 most common _____________ are solids, liquids, gases and plasmas. The _______________ are

Savatey [412]

The 4 most common States of matter are solids, liquids, gases and plasmas. The States of matter are also called the phases of matter.

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3. Changing from one state of matter to another is called a phase change. Solids can phase change to liquids or gasses. Liquids can phase change to solids or gasses. Gasses can phase change to liquids or solids.

4. Frost forms from water vapor depositing as ice crystal without first becoming liquid water. This is called Deposition. Deposition is also used in industry to put a thin layer of aluminum on mylar for helium balloons and for potato chip bags.

5. Put wet laundry outside on a clothes line in freezing weather and it will dry. The process is called Sublimation and a solid phase changes to a gas without first melting into a liquid. Dry ice (frozen CO2) undergoes Sublimation and becomes CO2 gas. It skips the liquid state and because we see something that looks like normal ice disappear without making a puddle, we call it dry ice.

6. Vaporization is when a liquid becomes a gas. It can happen slowly at cool temperatures and this is called evaporation. Or it can happen faster at the boiling temperature of the liquid and this is called boiling.

7. In the summer time, I love a glass filled with ice water. But water vapor in the air undergoes Condensation and becomes liquid water on the outside of the glass. Fog and clouds are also formed by Condensation of atmospheric water (water vapor) condensing into liquid water drops.

8. Thermic refers to thermal energy, usually perceived as heat or temperature. Endo refers to “inside.” Endothermic means heat is moving INTO a process and is stored in the products of that process. Heating up liquid water is Endothermic because heat is being put into the process of raising the water temperature and is stored in the kinetic motion of the water molecules. Melting ice into liquid water is Endothermic because heat is being used to break most of the attractive bonds between water molecules so that the molecules are still close to each other, but can slide around each other.

9. Thermic refers to thermal energy, usually perceived as heat or temperature. Exo refers to “outside” like exiting a room to the outside. Exothermic means heat moving out of a process. The heat energy comes from energy stored as kinetic motion of the molecules and broken bonds of attraction. When liquid water cools down, heat comes out of the water and goes to the environment around the water. This is Exothermic. Liquid water undergoing the phase change to become solid water (ice) is Exothermic. The thermal energy absorbed to “melt” the ice is released as the ice freezes.

10. The Kinetic Theory of Matter theorizes that all matter is made of tiny particles (atoms and molecules) that are in constant motion. The amount of motion is an indication of the temperature. At absolute zero, all kinetic motion stops.

7 0

3 years ago

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Which of these items are made of cells? Check all that apply.

Katen [24]

Answer:

The correct answers are: Bacteria, Horses, Humans and Mushrooms.

Explanation:

All living organisms are made up of cells. A cell is a microscopic atomic unit and is made up of cytoplasm, one or more nuclei, and a membrane.

They are divided into eukaryotic cells (with nucleus) and prokaryotic cells (they do not have a nucleus).

Depending on the number of cells that living organisms have, they can be classified as single-celled organisms, which are made up of one cell. For example bacteria.

Or they can be multicellular organisms, formed by two or more cells, for example horses.

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3 years ago

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What is the quantity of heat energy required to convert 10g cube of ice at -30oC to steam at 120oC. also draw a graph of tempera

Nadusha1986 [10]

Answer:

The amount of energy required is 31.1692 kJ .

Explanation:

The transitions of water are as follows,

(243K ice to 273K ice to 273K water to 373k water to 373K steam to 393K steam)

The following required data is,

specific heat capacity of ice= 2.1 kJ/kg

specific heat capacity of water= 4.2 kJ/kg

specific heat capacity of ice= 1.996 kJ/kg

specific latent heat of fusion=334 kJ/kg

specific latent heat of vapourisation = 2260 kJ/kg

FORMULAS:-

temperature change=mc(T2-T1)

phase transistion = mL,

where, m=mass , c=specific heat capacity ,L = latent heat of fusion or vapourisation ,(T2-T1)= temparature change

Thus the total amount of heat is,

=mc(T4-T3) + mL + mc(T3-T2) + mL + mc(T2-T1)

= $10(10^{-3} )(2.1)(30)+10(10^{-3} )(334)+10(10^{-3} )(100)(4.2)+10(10^{-3} )(2260) +10(10^{-3} )(20)(1.996)$

=(0.3)(2.1) + (3.34) + (4.2) + (22.6) + (0.2)(1.996)

=31.1692 kJ.

3 0

3 years ago