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3 years ago

PLS HELP ME ASAPPPP. 50 POINTSSS

Physics

1 answer:

dybincka [34]3 years ago

4 0

Answer:

1.8 kj

Explanation:

Explanation:

A substance's specific heat tells you how much heat is required to increase the mass of

1 g

of that substance by

∘

The equation that establishes a rel;ationship between heat absorbed and change in temperature looks like this

⋅

, where

- heat absorbed

- the mass of the sample

- the specific heat of the substance

- the change in temperature, defined as the difference between the final temperature and the initial temperature of the sample

You have all the information needed to find the amount of heat required to increase the temperature of your sample of mercury by that many degrees Celsius, so just rearange the above equation and solve for

250.0

⋅

0.14

∘

⋅

(

−

)

∘

1820 J

I'll leave the answer rounded to two sig figs and expressed in kilojoules

1.8 kJ

Answer Explanation:

A substance's specific heat tells you how much heat is required to increase the mass of

1 g

of that substance by

∘

The equation that establishes a rel;ationship between heat absorbed and change in temperature looks like this

⋅

, where

- heat absorbed

- the mass of the sample

- the specific heat of the substance

- the change in temperature, defined as the difference between the final temperature and the initial temperature of the sample

250.0

⋅

0.14

∘

⋅

(

−

)

∘

1820 J

I'll leave the answer rounded to two sig figs and expressed in kilojoules

1.8 kJ

Answer link

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A car is traveling at an average speed of 70 m/s. How many km would the car travel in 6.5 hrs. ?

docker41 [41]

Answer:

<h2>38,769.23 miles</h2>

Explanation:

given:

A car is traveling at an average speed of 70 m/s.

find:

How many km would the car travel in 6.5 hrs. ?

solution:

distance = velocity over time

let velocity = 70 m/s

time = 6.5 hrs.

convert velocity 70 m/s into m/h for consistency of units.

<u>70 mi. </u> x <u>3600 sec.</u> = 252,000 mi/hour

sec. 1 hr.

now plugin values into the formula d = v/t

d = <u>252,000 miles/hour </u>

6.5 hours

d = 38,769.23 miles

therefore, the distance travelled in 6.5 hours with a speed of 70 m/s is 38,769.23 miles

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3 years ago

Two car horns are sounded creating two sound waves with frequencies that differ by a factor of three. How does the speed of the

Andrews [41]

Answer:

Remains the same

Explanation:

The speed of waves of higher and lower frequency both will be same.

the speed of sound in a medium is constant and independent of it's frequency. Moreover, when the frequency changes wavelength changes accordingly, such that their product remains constant.

we know that

υ×λ = constant = velocity

υ= frequency

λ= wavelength.

7 0

3 years ago

Sawyer launches his 180 kg raft on the Mississippi River by pushing on it with a force of 75N. How long must Sawyer push on the

Daniel [21]

Answer: 4.8 s

Explanation:

We have the following data:

$m=180 kg$ the mass of the raft

$F=75 N$ the force applied by Sawyer

$V=2 m/s$ the raft's final speed

$V_{o}=0 m/s$ the raft's initial speed (assuming it starts from rest)

We have to find the time $t$

Well, according to Newton's second law of motion we have:

$F=m.a$ (1)

Where $a$ is the acceleration, which can be expressed as:

$a=\frac{\Delta V}{\Delta t}=\frac{V-V_{o}}{t-t_{o}}$ (2)

Substituting (2) in (1):

$F=m\frac{V-V_{o}}{t-t_{o}}$ (3)

Where $t_{o}=0$

Isolating $t$ from (3):

$t=\frac{m(V-V_{o})}{F}$ (4)

$t=\frac{180 kg(2 m/s-0 m/s)}{75 N}$

Finally:

$t=4.8 s$

6 0

3 years ago

Consider a roller coaster begins 15m above the ground. If the cart has a mass of 75kg, what is the velocity of the cart halfway

SashulF [63]

Answer:

v = 12.12 m/s

Explanation:

Given that,

The mass of the cart, m = 75 kg

The roller coaster begins 15 m above the ground.

We need to find the velocity of the cart halfway to the ground. Let the velocity be v. Using the conservation of energy at this position, h = 15/2 = 7.5 m

$mgh=\dfrac{1}{2}mv^2\\\\v=\sqrt{2gh} \\\\v=\sqrt{2\times 9.8\times 7.5} \\\\v=12.12\ m/s$

So, the velocity of the cart is 12.12 m/s.

7 0

3 years ago

PLEASE HELP ASAP Which one of the following is a step used for balancing chemical equations?

scZoUnD [109]

Answer:

C. Count the atoms in each substance in the reactants and products.

Explanation:

A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.

In order for a chemical equation to be balanced, the condition which must be met is that the number of atoms in the reactants equals the number of atoms in the products.

This ultimately implies that, the mass and charge of the chemical equation are both balanced properly.

In Chemistry, all chemical equation must follow or be in accordance with the Law of Conservation of Mass, which states that mass can neither be created nor destroyed by either a physical transformation or a chemical reaction but transformed from one form to another in an isolated (closed) system.

One of the step used for balancing chemical equations is to count the atoms in each substance in the reactants and products.

For example;

NH3 + O2 -----> NO + H2O

The number of atoms in each chemical element are;

For the reactant side:

Nitrogen, N = 1

Hydrogen, H = 3

Oxygen, O = 2

For the product side;

Nitrogen, N = 1

Hydrogen, H = 2

Oxygen, O = 2

When we balance the chemical equation, we would have;

NH3 + 3O2 -----> 4NO + 2H2O

3 0

3 years ago