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
cupoosta [38]
3 years ago
7

A car traveled 80 kilometers in 4 hours. Its average speed was _________.

Physics
2 answers:
Maru [420]3 years ago
8 0

Answer:

20  kilometers per hour

Explanation:

Divide 80 ÷ 4 = 20

Rate as brainliest

Masteriza [31]3 years ago
8 0

Answer:

20

Explanation:

Use the formula of speed, distance and time:

Distance = 80km

Speed = 4 hours

Speed = distance / time

Speed = 80 / 4

Speed = 20

You might be interested in
An electric motor draws out 5 A of current from a 20 V battery. How much power is it using?
irinina [24]

Answer:

Explanation:

P = VI = 20(5) = 100 W

7 0
3 years ago
Read 2 more answers
How does the transfer of thermal energy occur?
natali 33 [55]
Heat<span> may be </span>transferred<span> by means of conduction, convection, or radiation. </span>
8 0
3 years ago
What is non-point source pollution, and why is this kind of pollution hard to monitor and control?
antoniya [11.8K]

The use of pesticides in farming land is example of non-point source pollution. The area of emitting of pollution is very large. That is why, it is difficult to monitor and control this type of pollution.

Americans get their water for everyday use through aquifer. Aquifers can be conserve by avoiding high amount of chemical uses and reducing household waste. Also the sustainable use of water cause conservation of natural resource.

Aquifer are basically underground water present in ground pores. The structure of aquifer just look like sponge. The water moves through the porous surfaces of the ground.

7 0
3 years ago
A brick of mass 5 kg is released from rest at a height of 3 m. How fast is it going when it hits the ground? Acceleration due to
sineoko [7]

Taking into account the definition of kinetic, potencial and mechanical energy, when the brick hits the ground, it has a speed of 7,668 m/s.

<h3>Kinetic energy</h3>

Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.

Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and at rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless there is a change in speed or the body returns to its state of rest by applying a force.

The kinetic energy is represented by the following expression:

Ec= ½ mv²

Where:

  • Ec is the kinetic energy, which is measured in Joules (J).
  • m is the mass measured in kilograms (kg).
  • v is the speed measured in meters over seconds (m/s).

<h3>Potential energy</h3>

On the other hand, potential energy is the energy that measures the ability of a system to perform work based on its position. In other words, this is the energy that a body has at a certain height above the ground.

Gravitational potential energy is the energy associated with the gravitational force. This will depend on the relative height of an object to some reference point, the mass, and the force of gravity.

So for an object with mass m, at height h, the expression applied to the gravitational energy of the object is:

Ep= m×g×h

Where:

  • Ep is the potential energy in joules (J).
  • m is the mass in kilograms (kg).
  • h is the height in meters (m).
  • g is the acceleration of fall in m/s².
<h3>Mechanical energy</h3>

Finally, mechanical energy is that which a body or a system obtains as a result of the speed of its movement or its specific position, and which is capable of producing mechanical work. Then:

Potential energy + kinetic energy = total mechanical energy

<h3>Principle of conservation of mechanical energy </h3>

The principle of conservation of mechanical energy indicates that the mechanical energy of a body remains constant when all the forces acting on it are conservative (a force is conservative when the work it does on a body depends only on the initial and final points and not the path taken to get from one to the other.)

Therefore, if the potential energy decreases, the kinetic energy will increase. In the same way, if the kinetics decreases, the potential energy will increase.

<h3>This case</h3>

A brick of mass 5 kg is released from rest at a height of 3 m. Then, at this height, the brick of mass has no speed, so the kinetic energy has a value of zero because it depends on the speed or moving bodies. But the potential energy is calculated as:

Ep= 5 kg× 9.8 \frac{m}{s^{2} }× 3 m

Solving:

<u><em>Ep= 147 J</em></u>

So, the mechanical energy is calculated as:

Potential energy + kinetic energy = total mechanical energy

147 J +  0 J= total mechanical energy

147 J= total mechanical energy

The principle of conservation of mechanical energy  can be applied in this case. Then, when the brick hits the ground, the mechanical energy is 147 J. In this case, considering that the height is 0 m, the potential energy is zero because this energy depends on the relative height of the object. But the object has speed, so it will have kinetic energy. Then:

Potential energy + kinetic energy = total mechanical energy

0 J +  kinetic energy= 147 J

kinetic energy= 147 J

Considering the definition of kinetic energy:

½  5 kg×v²= 147 J

v=\sqrt{\frac{2x147 J}{5 kg} }

v=7.668 m/s

Finally, when the brick hits the ground, it has a speed of 7,668 m/s.

Learn more about mechanical energy:

brainly.com/question/17809741

brainly.com/question/14567080

brainly.com/question/12784057

brainly.com/question/10188030

brainly.com/question/11962904

#SPJ1

6 0
2 years ago
Do anyone k ow the answers?
OLga [1]
Hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
7 0
3 years ago
Other questions:
  • Describe 3 ways a bicyclist can change velocity.
    14·2 answers
  • Rank the pressures from highest to lowest:
    13·1 answer
  • A solar-powered car is traveling at constant speed around a circular track. what happens to the centripetal acceleration of the
    7·1 answer
  • The change of phase from a solid to a gas is called _____. evaporation melting sublimation vaporization
    10·2 answers
  • How long does it take me to travel 500 m at a speed of 50 m/s?
    13·2 answers
  • What forces cause the Sun’s magnetic field to become both stronger and more tangled
    10·1 answer
  • Determine the pressure point in a liquid container within a pool. The height of the liquid column is 9 m, The density of the liq
    8·1 answer
  • A roller coaster uses the track in this picture. Where will the roller coaster car have the most potential energy?
    11·1 answer
  • Choose the following types of hazards below
    9·2 answers
  • What is the definition of period in physics <br><br> In your own words
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!