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
romanna [79]
3 years ago
11

The average speed of a runner in a 400 meter race was 8.0 meters per second how long did it take the runner to complete the race

Physics
2 answers:
Mila [183]3 years ago
8 0
If it is eight meters per second, and the total distance he has to travel is four hundred meters to complete the race, you divide the total length needed to travel by the average speed per second to see the amount of seconds required to complete the race at that speed.

8 meters per second: Speed of runner
400 meters: Total distance

400/8=50

50 seconds to complete the race at the eight of 8m/s.
erik [133]3 years ago
7 0

Answer:

If it is eight meters per second, and the total distance he has to travel is four hundred meters to complete the race, you divide the total length needed to travel by the average speed per second to see the amount of seconds required to complete the race at that speed.8 meters per second: Speed of runner400 meters: Total distance400/8=50.50 seconds to complete the race at the eight of 8m/s.

You might be interested in
How long do molecules of groundwater stay in the ground?
Brilliant_brown [7]

CORRECT ANSWER:

d. Anywhere from days to thousands of years.

STEP-BY-STEP EXPLANATION:

The whole question from book is

How long do molecules of groundwater stay in the

ground?

a. Days

b. Weeks

c. Months

d. Anywhere from days to thousands of years

4 0
3 years ago
Read 2 more answers
A car of mass m, traveling at constant speed, rides over the top of a round hill. How do the normal force of the road on the car
dybincka [34]

Answer:

The normal force will be lower than the gravitational force acting on the car. Therefore the answer is N < mg, which is <em>option B</em>.

Explanation:

Over a round hill, the centripetal force acting toward the the radius of the hill supports the gravitational force (mg) of the car. This notion can be expressed mathematically as follows:

At the top of a round hill

Normal force = Gravitational force - centripetal force

At the foot of a round hill

Normal Force = centripetal force + Gravitational force

4 0
3 years ago
Could I please get some help on this question I don’t understand .
Oksana_A [137]

Answer:

12.5 m/s

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 0 m/s

Height (h) = 8 m

Final velocity (v) at 8 m above the lowest point =?

NOTE: Acceleration due to gravity (g) = 9.8 m/s²

The velocity of the roller coaster at 8 m above the lowest point can be obtained as follow:

v² = u² + 2gh

v² = 0² + (2 × 9.8 × 8)

v² = 0 + 156.8

v² = 156.8

Take the square root of both side

v = √156.8

v = 12.5 m/s

Therefore, the velocity of the roller coaster at 8 m above the lowest point is 12.5 m/s.

5 0
3 years ago
A very long insulating cylinder has radius R and carries positive charge distributed throughout its volume. The charge distribut
blsea [12.9K]

Answer:

1.E(r) = \frac{\alpha}{4\pi \epsilon_0}(2 - \frac{r}{R})

2.E(r) = \frac{1}{4\pi \epsilon_0}\frac{\alpha R}{r}

3.The results from part 1 and 2 agree when r = R.

Explanation:

The volume charge density is given as

\rho (r) = \alpha (1-\frac{r}{R})

We will investigate this question in two parts. First r < R, then r > R. We will show that at r = R, the solutions to both parts are equal to each other.

1. Since the cylinder is very long, Gauss’ Law can be applied.

\int {\vec{E}} \, d\vec{a} = \frac{Q_{enc}}{\epsilon_0}

The enclosed charge can be found by integrating the volume charge density over the inner cylinder enclosed by the imaginary Gaussian surface with radius ‘r’. The integration of E-field in the left-hand side of the Gauss’ Law is not needed, since E is constant at the chosen imaginary Gaussian surface, and the area integral is

\int\, da = 2\pi r h

where ‘h’ is the length of the imaginary Gaussian surface.

Q_{enc} = \int\limits^r_0 {\rho(r)h} \, dr = \alpha h \int\limits^r_0 {(1-r/R)} \, dr = \alpha h (r - \frac{r^2}{2R})\left \{ {{r=r} \atop {r=0}} \right. = \alpha h (\frac{2Rr - r^2}{2R})\\E2\pi rh = \alpha h \frac{2Rr - r^2}{2R\epsilon_0}\\E(r) = \alpha \frac{2R - r}{4\pi \epsilon_0 R}\\E(r) = \frac{\alpha}{4\pi \epsilon_0}(2 - \frac{r}{R})

2. For r> R, the total charge of the enclosed cylinder is equal to the total charge of the cylinder. So,

Q_{enc} = \int\limits^R_0 {\rho(r)h} \, dr = \alpha \int\limits^R_0 {(1-r/R)h} \, dr = \alpha h(r - \frac{r^2}{2R})\left \{ {{r=R} \atop {r=0}} \right. = \alpha h(R - \frac{R^2}{2R}) = \alpha h\frac{R}{2} \\E2\pi rh = \frac{\alpha Rh}{2\epsilon_0}\\E(r) = \frac{1}{4\pi \epsilon_0}\frac{\alpha R}{r}

3. At the boundary where r = R:

E(r=R) = \frac{\alpha}{4\pi \epsilon_0}(2 - \frac{r}{R}) = \frac{\alpha}{4\pi \epsilon_0}\\E(r=R) = \frac{1}{4\pi \epsilon_0}\frac{\alpha R}{r} = \frac{\alpha}{4\pi \epsilon_0}

As can be seen from above, two E-field values are equal as predicted.

4 0
3 years ago
A pickup truck is being driven down the highway carrying eight 100 gallon fish tank full of water. A hole is punctured in each t
irakobra [83]

Answer:

Explanation:

The velocity of the vehicle would increase because the the tanks (when filled with water) must have exerted a force which would reduce the velocity of the vehicle at a certain pressure on the gas pedal. Note that force equals mass multiplied by acceleration; as the mass decreases, so the force decreases. Thus, when the mass exerted by this tanks (on the vehicle) decrease as a result of the hole punctured in them, the force exerted by the tanks would also decrease causing an increase in velocity of the pick up truck when the same pressure is applied on the gas pedal throughout (before and after the puncture).

The conservation law that applied here is the law of conservation of energy which states that energy can neither be created nor destroyed but can be transformed from one form to another. This is because the energy the vehicle used in carrying the load (the tanks) was transformed to the energy that resulted in increasing  it's velocity (no new energy was formed as the pressure on the gas pedal remained the same).

6 0
3 years ago
Other questions:
  • Explain the advantages and disadvantages of using concentric circles in describing the solar system to an elementary school chil
    9·1 answer
  • A bicycle and its rider have a combined mass of 80 kg and a speed of 6 m/s. What is the magnitude of the average force needed to
    11·2 answers
  • The figure shows a positive charge placed in a uniform electric field. Is the force exerted on the +1 C charge directed up or do
    15·2 answers
  • Explain how the earth is round and not flat
    14·2 answers
  • Global Precipitation Measurement (GPM) is a tool scientists use to forecast weather. Which statements describe GPM? Select three
    7·1 answer
  • What is the bone in your arm
    14·2 answers
  • Chemistry The iron atom (Fe) has 26 protons, 30 neutrons, and 26 electrons. The diameter of the atom is approximately 1.0 × 10 −
    15·1 answer
  • g it as been suggested that solar powered space ships could get a boost from a laser either on earth or in orbit around earth. t
    8·1 answer
  • A force of 100 N acts on a body and moves at a distance of 2 m in the direction of the force. How much work has been done?
    14·1 answer
  • The velocity (in m/s) of a free-falling object as a function of the height from which it is dropped is
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!