All categories

4 years ago

The sum of potential and kinetic energies in the particles of a substance is called energy. True or False

Physics

1 answer:

harina [27]4 years ago

7 0

<h2>Answer: False</h2>

Explanation:

This sentence is the description of the mechanical energy.

In this sense, the mechanical energy of a body or a system is that which is obtained from the speed of its movement (kinetic energy) or its specific position (potential energy), in order to produce a mechanical work.

That is to say: The mechanical energy involves both the kinetic energy and the potential energy (which can be elastic or gravitational, for example).

In addition, it should be noted that mechanical energy is<u> conserved in conservative fields and is a scalar magnitude.</u>

Therefore:

<h2>The sum of potential and kinetic energies in the particles of a substance is called <u>Mechanical Energy</u></h2>

You might be interested in

Can somebody help please !<br><br> a. -8.3 m/s<br> b.-4.2 m/s<br> c.-0.12 m/s<br> d. 0 m/s

Gnom [1K]

The answer is a
$the \: answer \: is \: a.$

4 0

3 years ago

A sample of copper has a volume of 23.4 cm3 if the density of copper is 8.9 gcm3 what is the coppers mass?

murzikaleks [220]

The answer is: " 208 g " .
_____________________________________________
Explanation:
__________________________________________
The formula/ equation for density is:
__________________________________________
D = m / V ; That is, "mass divided by volume" ;

Density is expressed as:
__________________________________________
   "mass per unit volume"; in which the "mass" is expressed in units of "g" ("grams") ; and the "unit volume" is expressed in units of:
"cm³ " or "mL";
_____________________________________________
{Note the exact equivalent: 1 cm³ = 1 mL }.
____________________________________________
→ The formula is: " D = m / V " ;
___________________________________________
in which:

"D" refers to the "density" (see above), which is: "8.9 g/cm³ " (given);

"m" refers to the "mass" , in units of "g" (grams), which is unknown; and we want to find this value;

"V" refers to the "volume", in units of "cm³ " ;
which is: "23.4 cm³ " (given);
_________________________________________________
We want to find the mass, "m" ; so we take the original equation/formula for the density:
_________________________________________________
D = m / V ;
_________________________________________________________
And we rearrange; to isolate "m" (mass) on ONE side of the equation; and then we plug in our known/given values;
to solve for "m" (mass); in units of "g" (grams) ;
___________________________________________________
Multiply each side of the equation by "V" ;
____________________________________________________
V * { D = m / V } ; to get:
____________________________________________________
V * D = m ;   ↔ m = V * D ;
___________________________________________________
Now, we plug in the given values for "V" (volume) and "D" (density) ; to solve for the mass, "m" ;
______________________________________________________
m = V * D ;

m = (23.4 cm³) * (8.9 g / 1 cm³) = (23.4 * 8.9) g = 208.26 g ;

→ Round to "208 g" (3 significant figures);
____________________________________
The answer is: " 208 g " .
_____________________________________________________

7 0

3 years ago

You throw a ball downward from a window at a speed of 2.0m/s. How far has it fallen in 3 seconds?

bekas [8.4K]

Let's just assume that you throw the ball with an initial speed of 2 m/s instead of dropping it like free falling.
a=9.81 m/s^2
Vi= 2 m/s
t= 3 x

we use the formula
d = (Vi)(t) + (1/2)(a)(t)^2
d= (2)(3) + (1/2)(9.81)(9)
d=50.145 m

3 0

4 years ago

A cart traveling at 0.3 m/s collides with stationary object. After the collision, the cart rebounds in the opposite direction. T

miv72 [106K]

Answer:

C. In the first collision has twice the momentum as when it stays still ( second colllions)

Explanation:

To see which statement is correct, it is best to solve the problem, the momentum is equal to the variation of the moment

I = Δp = m vf - m v₀

I = m (vf -v₀)

Case 1. In car bounces, the initial speed is 0.3 m / s, say that this direction is positive, when the magnitude of the speed bounces it remains constant, but its direction is reversed (vf = -0.3 m / s)

I₁ = m (-0.3 - 0.3)

I₁ = -0.6 m

Case 2. The expensive one that still after the crash so its speed is zero (vf = 0)

I₂ = m (0 - 0.3)

I₂ = -0.3 m

Let's calculate the relationship between the two impulses

I₁ / I₂ = -0.6m / -0.3m

I₂ / I₂ = 2

When it bounces it has twice the momentum as when it stays still

Now let's analyze the answers:

A. False The momentum changes

B. False. The momentum is less in the second collision

C. True. The momentum is double in this collision

D. False. Can be calculated, because the mass is the same throughout the exercise and is eliminated in the equations

E. False. When they say bounces it implies the same speed with the opposite direction

4 0

3 years ago

The reactants for a certain chemical reaction are shown. Cu(NO3)2 + NaOH → Which of the following shows the correct product or p

valentinak56 [21]

Answer : The products of this reaction are, $Cu(OH)_2$ and $NaNO_3$

Explanation :

First we have to write the balanced chemical reaction.

$Cu(NO_3)_2+2NaOH\rightarrow Cu(OH)_2+2NaNO_3$

In this reaction, 1 mole of copper nitrate react with the 2 moles of sodium hydroxide to give 1 mole of copper hydroxide and 2 moles of sodium nitrate.

This reaction is a double displacement reaction.

Double displacement reaction : A type of reaction in which a positive cation and a negative anion of two reactants react to exchange their places to form two new products.

The general representation of this reaction is,

$XY+AB\rightarrow XB+AY$

(X and A are the cations, Y and B are the anions)

Hence, the products of this reaction are, copper hydroxide, $Cu(OH)_2$ and sodium nitrate, $NaNO_3$

6 0

3 years ago