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inysia [295]
3 years ago
15

Ellen needs to move a heavy box across the floor and then place it on a shelf that is four feet above the floor. Which use of ma

chines would most likely require the least amount of force in order to get the box on the shelf?
A. sliding the box up an inclined plane to the shelf
B. rolling the box up an inclined plane on a cart
C. sliding the box across the floor and then lifting it using a pulley
D. rolling the box across the floor in a cart and then using a pulley
Physics
2 answers:
dusya [7]3 years ago
4 0
<span>D. rolling the box across the floor in a cart and then using a pulley </span>
slava [35]3 years ago
4 0

The answer among the choices is option C. Sliding the box across the floor and lifting it using a pulley.

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"A light beam incident on a diffraction grating consists of waves with two different wavelengths. The separation of the two firs
Fantom [35]

Answer:

A light beam incident on a diffraction grating consists of waves with two different wavelengths. The separation of the two first order lines is great if

the dispersion is great

6 0
3 years ago
A 26.0 kg child plays on a swing having support ropes that are 2.40 m long. A friend pulls her back until the ropes are 45.0 ∘ f
Sloan [31]
A)Ep'=mgh=mgl(1-cosa).At the bottom of the swing Ep=0(reference level),so the potential energy as the child is just released is bigger than the potential energy at the bottom of the swing.;B)The speed of the child at the bottom of the swing-->v=√(2gh)=√[2gl(1-cosa)];C)I don't think that the tension does any work.
8 0
3 years ago
What is the volume of a rock with a density of 3.00 g/cm3 and a mass of 600g?
Mademuasel [1]
The equation of D = m/V

Where D = density
m = mass
and V = volume

We are solving for V, so with the manipulation of variables we multiply V on both sides giving us 
V(D) = m 
now we divide D on both sides giving us
V = m/D 

We know our mass which is 600g and our density is 3.00 g/cm^3
so
V = 600g/3.00g/cm^3 = 200cm^3  or 200mL

a cubic centimeter (cm^3) is one of the units for volume. It's exactly like mL. 1 cm^3 = 1 mL
 
If you wish to change it to L, you'd have to convert. 
5 0
3 years ago
17. A volleyball weighs about 300 grams.
atroni [7]

Answer:

PE = 44.1 J

Explanation:

Ok, to have the specific data, the first thing we must do is convert from grams to kilograms. Since mass must always be in kilograms (kg)

We have:

  • 1 kilograms = 1000 grams.

We convert it using a rule of 3, replacing, simplifying units and solving:

  • \boxed{\bold{x=\frac{gr*1\ kg}{1000\ gr}=\frac{300\ gr*1\ kg}{1000\ gr}=\frac{300\ kg}{1000}=\boxed{\bold{0.3\ kg}}}}

==================================================================

Earth's gravity is known to be 9.8 m/s², so we have:

Data:

  • m = 0.3 kg
  • g = 9.8 m/s²
  • h = 15 m
  • PE = ?

Use formula of potencial energy:

  • \boxed{\bold{PE=m*g*h}}

Replace and solve:

  • \boxed{\bold{PE=0.3\ kg*9.8\frac{m}{s^{2}}*15\ m}}
  • \boxed{\boxed{\bold{PE=44.1\ J}}}

Since the decimal number, that is, the number after the comma is less than 5, it cannot be rounded, then we have this result.

The potential energy of the volleyball is <u>44.1 Joules.</u>

Greetings.

8 0
3 years ago
Isaac Newton published his work on gravity in the Philosophiæ Naturalis Principia Mathematica (Latin for Mathematical Principles
Igoryamba
Today we can make observations that would lead us to the same conclusion as newton. If you throw a baseball in the air, it always comes back down. This is because of gravity. duh.
6 0
3 years ago
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