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goblinko [34]
4 years ago
5

You are carrying a 7.0-kg bag of groceries as you walk at constant velocity along the sidewalk. You walk a distance of 82 meters

and hold the bag at a height of 1.5 m above the sidewalk. How much work against gravity do you do on the bag?
100 J

0 J

5600 J

82 J
Physics
1 answer:
MAVERICK [17]4 years ago
7 0

Answer:

0J

Option: B

Explanation:

Work is done when something is moved by the force in the direction of the force. That is the force (e.g., the weight) and the direction the object moves must be aligned for work to be done. In this given condition, the direction is horizontal and the force is downward as its gravity force. That 90° between the two vectors.

The work function is W = m × g ×h × cosθ

\text { Where, in this case theta }=90^{\circ}

Hence,  

Work done = 7 × 9.8 × 1.5 × cos(90)  

Work done = 0 (cos90^{\circ} = 0)

Work done = 0

Therefore work done is 0 J.

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It's lead.  That's why the "apron" is so heavy.
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As you may well know, placing metal objects inside a microwave oven can generate sparks. Two of your friends are arguing over th
Fofino [41]

Answer:

5.04\cdot 10^8 A

Explanation:

The work function of the metal corresponds to the minimum energy needed to extract a photoelectron from the metal. In this case, it is:

\phi = 3.950\cdot 10^{-19}J

So, the energy of the incoming photon hitting on the metal must be at least equal to this value.

The energy of a photon is given by

E=\frac{hc}{\lambda}

where

h is the Planck's constant

c is the speed of light

\lambda is the wavelength of the photon

Using E=\phi and solving for \lambda, we find the maximum wavelength of the radiation that will eject electrons from the metal:

\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{3.950\cdot 10^{-19} J}=5.04\cdot 10^{-7}m

And since

1 angstrom = 10^{-15}m

The wavelength in angstroms is

\lambda=\frac{5.04\cdot 10^{-7} m}{10^{-15} m/A}=5.04\cdot 10^8 A

3 0
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Which observation BEST supports evidence that two different species share a common ancestor? A) they both prey on the same anima
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Ne4ueva [31]

Answer:

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4 0
3 years ago
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Match the following:
Nadusha1986 [10]

Answer:

Statement 1 can be matched with option f (Van der waal forces)

Statement 2 can be matched with option b (Liquid crystal)

statement 3 can be matched with option e (Thermal expansion)

Statement 4 can be matched with option g (Viscosity)

Statement 5 can be matched with option b (Fractional distillation)

Statement 6 can be matched with option a (Diffusion)

Statement 7 can be matched with option d (Miscible)

Explanation:

  1. Van der waal forces are weak inter-molecular bonds found between covalent molecules e.g molecules of graphite, noble gases etc
  2. Liquid crystals are substances that behave like liquids and its molecules orientate itself like a crystal (solid). They can be referred to as LCs.
  3. Thermal expansion is a phenomenon where by matter changes in shape, volume and area due to a change in temperature.
  4. Viscosity is a term used to describe a fluid's resistance to flow. It is also used to describe the internal friction that a moving liquid experiences. Oil is more viscose than liquid water
  5. Fractional distillation is a separation technique used in separating two or more miscible liquids of close boiling points. For example petrol and diesel oil can be separated using fractional distillation. An industrial application of this technique is Fractional distillation of crude oil where crude oil is separated into its components
  6. Diffusion is the movement of dissolved particles, gases, liquid from a region of higher concentration to a region of lower concentration until there is a equal balance. This can occur when you spray a perfume in one end of a room. You will get to smell the perfume at the other end after some time. Diffusion is fastest in gas as compared to liquids and solids.
  7. Miscible is a word used to describe liquids forming a homogeneous mixture when dissolved in each other. Miscibility is factor to be considered when separating mixture.
7 0
3 years ago
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