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luda_lava [24]
3 years ago
11

1. How much work is done on a 20-N rock that you lift 1.5 meters up?

Physics
1 answer:
Tcecarenko [31]3 years ago
3 0

The answer will be B

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1pt A cannon fires a 5-kg ball horizontally from a
Klio2033 [76]

Answer: Both cannonballs will hit the ground at the same time.

Explanation:

Suppose that a given object is on the air. The only force acting on the object (if we ignore air friction and such) will be the gravitational force.

then the acceleration equation is only on the vertical axis, and can be written as:

a(t) = -(9.8 m/s^2)

Now, to get the vertical velocity equation, we need to integrate over time.

v(t) = -(9.8 m/s^2)*t + v0

Where v0 is the initial velocity of the object in the vertical axis.

if the object is dropped (or it only has initial velocity on the horizontal axis) then v0 = 0m/s

and:

v(t) = -(9.8 m/s^2)*t

Now, if two objects are initially at the same height (both cannonballs start 1 m above the ground)

And both objects have the same vertical velocity, we can conclude that both objects will hit the ground at the same time.

You can notice that the fact that one ball is fired horizontally and the other is only dropped does not affect this, because we only analyze the vertical problem, not the horizontal one. (This is something useful to remember, we can separate the vertical and horizontal movement in these type of problems)

7 0
3 years ago
Determina el tamaño de la arista de un cubo hecho de plata, cuya masa es de 10.49 kg.
Sidana [21]

Answer:

88.2 N

Explanation:

Datos

Lcubo = 10 cm = 0.1 m

Vcubo = Vfluido desalojado= 0.1 m x 0.1 m x 0.1 m = 10-3 m

mcubo = 10 kg

dfluido = 1000 kg/m3

g = 9.8 m/s2  

Sabemos que el peso aparente de un cuerpo que se sumerge en un fluido es:

Paparente=Preal−Pfluido

Teniendo en cuenta que:

Preal = mcubo⋅gPfluido=E= dfluido⋅Vfluido⋅g

Como el cuerpo se sumerge completamente en el fluido, el volumen de fluido desalojado es exactamente el volumen del cubo. Por lo tanto si sustituimos los datos que nos proporcionan en el enunciado en la primera ecuación:

Paparente=mcubo⋅g−dfluido⋅Vfluido⋅g ⇒Paparente=10 kg ⋅9.8 m/s2 − 1000 kg/m3 ⋅10−3 m ⋅9.8 m/s2 ⇒Paparente = 88.2 N

7 0
3 years ago
A circle has an initial radius of 50ft when the radius begins decreasing at a rate of 2ft/s. what is the rate of change of the a
valkas [14]
The area of the circle with radius r is
A = πr²

The rate of change of area with respect to time is
\frac{dA}{dt} = \frac{dA}{dr} . \frac{dr}{dt} =2 \pi r. \frac{dr}{dt}

The rate of change of the radius is given as
\frac{dr}{dt} =-2 \,  \frac{ft}{s}
Therefore
\frac{dA}{dt} =-4 \pi r \,  \frac{ft^{2}}{s}

When r = 10 ft, obtain
\frac{dA}{dt}|_{r=10 \, ft} = -40 \pi  \,  \frac{ft^{2}}{s}

Answer: - 40π ft²/s (or - 127.5 ft²/s)
7 0
3 years ago
Which of the following is true A. If the sum of the external forces on an object is zero, then the object must be in equilibrium
yanalaym [24]

Answer:

A. If the sum of the external forces on an object is zero, then the object must be in equilibrium

Explanation:

Equilibrium, in physics, the condition of a system when neither its state of motion nor its internal energy state tends to change with time.

For a single particle, equilibrium arises if the vector sum of all forces acting upon the particle is zero.

the object is at equilibrium, then the net force acting upon the object should be 0 Newton. Thus, if all the forces are added together as vectors, then the resultant force (the vector sum) should be 0 Newton.

There are three types of equilibrium: stable, unstable, and neutral

3 0
3 years ago
What solutes do not dissolve well in water?
hammer [34]

Answer:

Many substances do not dissolve in water and that is because they are non-polar and do not interact well with water molecules. A common example is oil and water. Oil contains molecules that are non-polar, thus they do not dissolve in water.

Explanation:

6 0
3 years ago
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