1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
ddd [48]
3 years ago
9

A person is standing on and facing the front of a stationary skateboard while holding a construction brick. The mass of the pers

on is 67.0 kg, the mass of the skateboard is 4.10 kg, and the mass of the brick is 2.50 kg. If the person throws the brick forward (in the direction they are facing) with a speed of 23.0 m/s relative to the skateboard and we ignore friction, determine the recoil speed of the person and the skateboard, relative to the ground.
Physics
1 answer:
Inessa [10]3 years ago
6 0

Answer:

    v₁ = -0.8087 m / s

Explanation:

To solve this problem we can use the conservation of momentum, for this we define a system formed by the man, the skateboard and the brick, therefore the force during the separation is internal and the momentum is conserved

Initial instant. When they are united

        p₀ = 0

Final moment. After throwing the brick

        p_{f} = (m_man + m_skate) v1 + m_brick v2

the moment is preserved

        p₀ = p_{f}

        0 = (m_man + m_skate) v₁ + m_brick v₂

        v₁ = -  \frac{ m_{brick}   }{m_{man} + m_{skate}   }  v_{2}

the negative sign indicates that the two speeds are in the opposite direction

let's calculate

        v₁ = - \frac{2.5}{67 + 4.10}  23.0

        v₁ = -0.8087 m / s

You might be interested in
Why do things become hot or cold?<br> Relate to Thermal Energy and The Law of Conservation of Energy
Mekhanik [1.2K]

<u>Answer:</u>

Things become hot and cold because of the transfer of energy.

<u>Explanation:</u>

The energy possessed by an object or system is called thermal energy and heat is the flow of this energy. While the law of conversation of energy states that energy is not destroyed or created, it just transfers from one object to another.  

When a hot object is placed in normal conditions, it transfers heat to the environment until both are at the same temperature and heat transfers from the environment to the cold objects placed in normal conditions.

4 0
3 years ago
Fill-in-the-blank test questions measure ________; matching concepts with their definitions measures ________.
Ulleksa [173]

Test questions measure recall; matching concepts with their definitions measures recognition.

<u>Explanation: </u>

According to Psychology our brain remembers everything what we learn but the understanding and remembering the right answer for the right question needs training and understanding ability. So in order to enhance the ability of recalling and recognizing among the students, the concept of test questions and matching with definitions are used in curricular activities.

As the students will be learning different terms, definitions, methods and different subjects, they should be able to distinguish among different definitions as well as they should recall the things they have learnt. So the answers for the test questions will help to recall the topics learnt by the students while the matching concept will help the students to recognize each definition with their terms.

6 0
3 years ago
The message refers to which of the following?
Oliga [24]

The message is the information being communicated from one place to another.

It used to be called the "intelligence".  But as time went on, it became
harder to ignore the obvious fact that that was going too far, and the
label was changed to the more IQ-neutral "message".    

7 0
3 years ago
How much total work is done by the force in lifting the elevator from 0.0 m to 9.0 m?
aksik [14]
The total work is

         (mass of the elevator, kg) x (9.8 m/s²) x (9.0 m)           Joules .
8 0
3 years ago
Which is the one factor that adds to the greenhouse effect? 1. a decrease in the amount of dust in the atmosphere 2. a decrease
lukranit [14]

Answer:

an increase in gasses that absorb heat

Explanation:

Greenhouse effect refers to the gradual increase in the earth's temperature due to an increase in the concentration of certain gases in the atmosphere. These gases are called greenhouse gases and they include; water vapour, nitrogen 1 oxide, carbon IV oxide etc. Green house effect is said to occur when heat radiating outwards from the earth surface towards space is trapped close to the earth's surface due to the presence of greenhouse gases in the atmosphere.

Greenhouse effect leads to increase in the temperature of the earth, melting of polar ice caps and possibly flooding due to a rise in sea levels.

Greenhouse gases act as glass in a greenhouse. They allow heat to pass through onto the earth surface but trap the heat and prevent it from being radiated outwards back to space. Thereby increasing the surface temperature of the earth.

8 0
3 years ago
Read 2 more answers
Other questions:
  • What happens when the kinetic energy of molecules increases so much that electrons are released by the atoms, creating a swirlin
    15·1 answer
  • What are some of the names given to the Moon by the Algonquin?
    12·1 answer
  • A 285-mL flask contains pure helium at a pressure of 750 torr . A second flask with a volume of 455 mL contains pure argon at a
    7·2 answers
  • Which statement is correct?
    13·2 answers
  • PLEASE HELP An object is thrown upward with an initial velocity of 32.1 m/s. What is its velocity in 4.0 s? (use g = 9.81 m/s2).
    7·1 answer
  • Ohm’s Law<br>pls answer this photos​
    13·1 answer
  • In your experiment, you measure a total deflection of 4.12 cm when an electric field of 1.10×103V/m is established between the p
    6·1 answer
  • A 55 kg person is in a head-on collision. The car's speed at impact is 12 m/s. Estimate the net force on the person if he or she
    12·1 answer
  • Which car has the most kinetic energy?
    12·1 answer
  • Hi how are you?<br><br>Answer only Philippines<br>​
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!