3. True or False: A warm-up can include minimal stretching at the end.

Answer:

3 to 7 seconds.

Explanation:

Answer with Explanation:

Let me answer this in a simple way, since the density of stone is greater than that of water, the stone sinks as the weight of the stone is greater than the weight of water displaced by it. But the ship is designed in such a way that the relative density of the ship always becomes less than that of water. Therefore, the weight of the water displaced becomes equal to the total weight of the ship and thus it floats.

There are many other ways to explain this but this should give you the general idea.

Answer:

Resistance is defined as the property of a conductor to resist the flow of charges through it. The resistance of conductor is numerically given as the ratio of potential difference across its length to the current flowing through it.

Explanation:

Answer:

The resistance of a thin wire is greater than the resistance of a thick wire because a thin wire has fewer electrons to carry the current. The relationship between resistance and the area of the cross section of a wire is inversely proportional .

The best way to think about this is:

A thick/wide road, with many lanes, can carry more cars than a thin/narrow road, with only one or two lanes.

Answer:

D. The overall enthalpy change for a reaction is independent of the route the reaction takes.

Answer: Hess's law states that the overall enthalpy change for a reaction is independent of the route the reaction takes. Option D is correct.

It is given Hess's law.

It is required to state the Hess's law.

Thermochemical equations can be manipulated to give the data chemical reactions. We find exactly how much energy will be absorbed or released by the reaction because we may face various explosions.

There are mainly two ways to calculate ΔH of any reaction. First If the reaction has ΔH then the reverse of the reaction will have opposite ΔH and the second is if double the ΔH of the substances, double the ΔH.

Therefore Hess's law states that the overall enthalpy change for a reaction is independent of the route the reaction takes.

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Answer:

But negative acceleration means that the rate of change of velocity is negative or velocity decreases. Example: (1) When we apply brakes in a moving car, then negative acceleration acts on it and the car stops. (2) When we throw a ball upwards, then also negative acceleration acts on it.

Explanation:

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MATHEMATICALLY A NEGATIVE ACCELERATION MEANS YOU WILL SUBTRACT FROM THE CURRENT VALUE OF THE VELOCITY.

It’s 180 m/s^2 dude. I think I have you in my class lol.

The centripetal acceleration of an object is due to the changing velocity in a circular path and the centripetal acceleration of the bicycle is 182.85 m/s².

Centripetal acceleration of an object can be defined as the property of the motion of an object which is traversing a circular path. Any object which is moving in a circular path and has an acceleration vector pointed towards the center of that circular path is known as Centripetal acceleration.

The centripetal acceleration of an object can be calculated by the formula:

ac = v²/ r

where, ac = centripetal acceleration,

v = velocity of the object,

r = radius of the circular path

The centripetal acceleration of the object will be:

ac = (8)²/ r

radius = diameter/ 2

radius = 70/ 2

radius = 35cm or 0.35 m

ac = 64/ 0.35

ac = 182.85 m/s²

Therefore, the centripetal acceleration of the bicycle will be 182.85 m/s².

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Answer:

13.759 % of the initial mechanical energy is lost as thermal energy.

Explanation:

By the First Law of Thermodynamics we know that increase in internal energy of the object ([tex]U[/tex]), in joules, is equal to the lost amount of the change in gravitational potential energy ([tex]U_{g}[/tex]), in joules:

[tex]\frac{x}{100} \cdot \Delta U_{g} = \Delta U[/tex] (1)

Where [tex]x[/tex] is the percentage of the energy loss, no unit.

By definition of the gravitational potential energy and internal energy, we expand this equation:

[tex]\frac{x\cdot m \cdot g \cdot h}{100} = m\cdot c\cdot \Delta T[/tex] (1b)

Where:

[tex]m[/tex] - Mass of the object, in kilograms.

[tex]g[/tex] - Gravitational acceleration, in meters per square second.

[tex]h[/tex] - Initial height of the object above the lunar ground, in meters.

[tex]c[/tex] - Specific heat of aluminium, in joules per degree Celsius-kilogram.

[tex]\Delta T[/tex] - Temperature increase due to collision, in degree Celsius.

If we know that [tex]m = 0.95\,kg[/tex], [tex]g = 9.807\,\frac{m}{s^{2}}[/tex], [tex]h = 75\,m[/tex], [tex]c = 920\,\frac{J}{kg\cdot ^{\circ}C}[/tex] and [tex]\Delta T = 0.11\,^{\circ}C[/tex], then the percentage of energy loss due to collision is:

[tex]x = \frac{100\cdot c\cdot \Delta T}{g\cdot h}[/tex]

[tex]x = \frac{100\cdot \left(920\,\frac{J}{kg\cdot ^{\circ}C} \right)\cdot (0.11\,^{\circ}C)}{\left(9.807\,\frac{m}{s^{2}} \right)\cdot (75\,m)}[/tex]

[tex]x = 13.759\,\%[/tex]

13.759 % of the initial mechanical energy is lost as thermal energy.

Answer:

4360 Kgm/s

Explanation:

Applying,

Ft = M-M'................. Equation 1

Where F = force, t = time, M = Final momentum, M' = Initial momentum.

make M the subject of the equation

M = Ft+M'............ Equation 2

From the question,

Given: F = 4000 N, t = 0.9 seconds, M' = 400 kg-m/s

Substitute these values into equation 2

M = 4000+(0.9×400)

M = 4000+360

M = 4360 kgm/s

Hence the final momentum is 4360 kgm/s

Answer: The mass of copper liberated is 0.196 g.

Explanation:

The oxidation half-reaction of copper follows:

[tex]Cu\rightarrow Cu^{2+}+2e^-[/tex]

Calculating the theoretical mass deposited by using Faraday's law, which is:

[tex]m=\frac{M\times I\times t(s)}{n\times F}[/tex] ......(1)

where,

m = actual mass deposited = ? g

M = molar mass of metal = 63 g/mol

I = average current = 2 A

t = time period in seconds = 5 min = 300 s (Conversion factor: 1 min = 60 sec)

n = number of electrons exchanged = 2

F = Faraday's constant = 96500 C/mol

Putting values in equation 1, we get:

[tex]m=\frac{63 g/mol\times 2A\times 300s}{2\times 96500 C/mol}\\\\m=0.196g[/tex]

Hence, the mass of copper liberated is 0.196 g.

It's the velocity, but only the magnitude. It can't show the direction of the velocity. So it's better to call it speed.

Answer:

difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.

Option ( iv ) is the correct answer.

A vector quantity the physical quantity that has both direction as well as magnitude.

Answer:

3.8 x 10^-5

Explanation:

all you doing is putting it in the standard form I hope this help

Answer:

v = 2.85 m/s

Explanation:

Given that,

A skipper on a boat notices wave crests passing his anchor chain every 5.6 s.

The distance between wave crests to be 16 m.

We need to find the speed of the waves. The speed of a wave can be calculated by the formula as follows :

[tex]v=f\lambda\\\\v=\dfrac{\lambda}{T}\\\\v=\dfrac{16}{5.6}\\\\v=2.85\ m/s[/tex]

So, the speed of the wave is 2.85 m/s.

Answer:

the process of comparing unknown quantities with known standards quantities are known as measurement

1) Two major factors, mass and distance, affect the strength of gravitational force on an object.

2) Most common factors that affect gravity are mass of the body, distance from centers, shape of bodies,etc. Gravity is a binding force, always acting to bind any material closure and closure inwards. If we think this way, then gravity is maximum at its centre and decreases slowly away from its centre.

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Explanation:

p = F /A

F = P×A

F = 30,000 Pa / 0.1 m²

F = 300,000 N

Answer:

An interaction of one object with another object results in a force between the two objects. Thus, at-least two objects must interact for a force to come into play.

Answer:

a)  [tex]h=25m[/tex]

b)  [tex]v=19.8m/sec[/tex]

Explanation:

From the question we are told that:

Height [tex]h=25m[/tex]

Bounce Height [tex]h'=20m[/tex]

Generally the Kinematic equation is mathematically given by

[tex]V=\sqrt{2gh}\\\\V=\sqrt{2*9.81*25}[/tex]

[tex]V=22.1m/sec[/tex]

Therefore Height

[tex]h=\frac{V^2}{2g}\\\\h=\frac{22.1^2}{2*9.81}[/tex]

[tex]h=25m[/tex]

b)

Generally the Kinematic equation is mathematically given by

[tex]v^2=2ah[/tex]

[tex]v^2=2*9.8*20[/tex]

[tex]v=\sqrt{2*9.8*20}[/tex]

[tex]v=19.8m/sec[/tex]

Answer: 40 grams, if it is two grams per mL and you have 20 mL, you multiply 2 grams/mL and you get the answer

Answer:

Explanation:

There is no pressure of your feet on the scales, and no pressure of the floor on the scales, so the scales will read zero*. Hence, your weight, in a freely falling lift is zero

Answer:

[tex]F = kmg \\ k = \frac{F}{mg} [/tex]

Explanation:

F = k . m . g

=> F = k . mg

[tex] = > k = \frac{F}{mg} (ans)[/tex]

Answer:

Alkaline batteries have longer shelf life than other batteries of the chloride type electrolyte batteries. They have a much higher energy density compared with other batteries. This allows the battery to produce the same energy while lasting longer than other batteries.

Advantage

1) Alkaline battery lasts long than other batteries  

2) It have a  much higher energy density

Disadvantage :

1) They are heavier and bulkier

2) They have high internal resistance

An alkaline battery is a type of primary battery that derives its energy from the reaction between zinc metal and manganese dioxide.

Advantage

Alkaline battery   can produce same amount of energy by lasting longer than other batteries  as it have longer shelf life than  lead acid accumulator​

Alkaline battery  have a much higher energy density compared to lead acid accumulator

Disadvantage :

Alkaline battery  are heavier and bulkier

Alkaline battery   have high internal resistance

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Answer:

V1 = 4/3 pi R^3 = pi D^3 / 6     D = 2 R       volume of sphere

V2 = pi r^2 L = pi d^2 L / 4       volume of wire

V2 / V1 = 1 = 3/2 d^2 L / D^3     since volumes are equal

L = 2/3 D^3 / d^2 = 2/3 * 6^3 / .02^2 = 360,00 cm = 3600 m

Explanation:

the correct answer is option ( C ) and ( D )

The magnitude of the teachers displacement is the difference between

the location of the school and the location of the doctors office

The reason behind the above expression are explained as follows

The known locations of the teacher;

Initial location; The school

Second location; The mall

The eventual location; The doctors office

The required information;

The magnitude of the teachers displacement

The method of obtaining the displacement of the teacher;

Qualitatively, the displacement of the teacher can be obtained by applying the definition of displacement as follows;

The definition of displacement is an object's change in position, given by the difference between its start and finish locations

According to the definition of displacement, therefore, the magnitude of

the teachers displacement is the distance between the school and the

doctors office which is given by the difference between the coordinates of

the location of the school and the location of the doctors office

The magnitude of the displacement of the teacher = The coordinate of the location of the doctors office - The coordinate of the location of the school

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Answer:

d. No, porque la ecuación de trabajo lo define.

Explanation:

En Física, el trabajo realizado se puede definir como la cantidad de energía transferida cuando un objeto o cuerpo se mueve a lo largo de una distancia debido a la acción de una fuerza externa.

Matemáticamente, el trabajo realizado viene dado por la fórmula;

[tex] W = F * d [/tex]

Dónde;

Por lo tanto, podemos deducir de la definición de trabajo y su fórmula que el trabajo se realiza cuando un objeto (cuerpo) se mueve una distancia o experimenta cualquier forma de desplazamiento mientras transfiere energía.