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
zysi [14]
3 years ago
14

A runner runs the first 400m of a race in 80s, the second 400m in 70s and the final 800m in 130s. What was her average speed for

this run?
Physics
1 answer:
-BARSIC- [3]3 years ago
5 0

Answer: The average speed is 5.71 m/s

Explanation:

The average speed in this run will be the quotient between the total distance that the runner traveled, and the total time it took.

Distance = 400m + 400m + 800m = 1600m

Time = 80s + 70s + 130s = 280s

Then the average speed is:

S = 1600m/280s = 5.71 m/s

You might be interested in
The molar weight of water vapor is about 18g per mole, while the molar weight of dry air is about 29g per mole since almost all
musickatia [10]

Answer:

The moist air mass would be denser

Explanation:

Density is defined as mass per unit volume. Hence the density of a substance (solid, liquid or gas) is directly proportional to its mass and inversely proportional to the volume occupied.

The mass of a gas is the product of its number of moles and its molar mass (mass = number of moles × molar mass), which indicates that the mass is directly proportional to molar mass, so the higher the molar mass, the higher the mass of different gases at equal volumes, temperature and pressure.

From the information given, the molar weight of dry air = 29g/mole.

The molar weight of moist air = molar weight of dry air + molar weight of water vapour = 29 + 18 = 47g/mole.

Therefore since higher molar mass transits to higher mass, it can be said that moist air of molar mass 47g/mole is denser than dry air of molar mass 29g/mole at equal volume, temperature and pressure.

Simple picture the two gasses in two transparent jars, the heavier gas (moist air) settles more at the bottom of the jar, and has less random motion hence is more compressed and denser, than dry air that has more freedom to move randomly because of its lesser weight.

4 0
3 years ago
The most intense earthquakes happen at
zhuklara [117]

Answer:

I would say d sry if im wrong

Explanation:

4 0
3 years ago
Examples of non viscous liquid​
Musya8 [376]

The fluids that have no resistance or zero resistance to internal friction are known as non- viscous fluids. • The fluid which has more resistance to flow is called viscous fluid. Viscosity is a property of a fluid, which is a degree of the amount of resistance between the fluid layers.

4 0
3 years ago
Ammeters should be connected ________ with the circuit being tested.
Viktor [21]
Always should be connected in series! :) 
3 0
4 years ago
If a boulder is dropped straight down off the edge of a vertical cliff, how long does it take it to reach 90 Km/h? Give in secon
Semmy [17]

Answer:

2.551 m/s

Explanation:

Given:

Boulder is dropped from the cliff

thus,

Initial speed of the boulder, u = 0 m/s

Final speed to be obtained, v = 90 km/h =90\times\frac{5}{18} =25 m/s

also, in the case of free fall the acceleration of the boulder will be equal to the acceleration due to the gravity i.e g = 9.8 m/s²

Now, from the Newton's equation of motion

v = u + at

where, a is the acceleration = g = 9.8 m/s²

t is the time

on substituting the respective values, we get

25 = 0 + 9.8 × t

or

t = \frac{\textup{25}}{\textup{9.8}}

or

t = 2.551 m/s

7 0
3 years ago
Other questions:
  • Gamma rays are a type of very high frequency wave. This means that gamma rays must have a _____.
    13·2 answers
  • Two balloons have a negative charge. What happened when they are bought near each other ?
    13·2 answers
  • How much work is needed to push a 5kg bookshelf 4.52 m with the force of 15.3N
    14·1 answer
  • A solution is a special mixture where you cannot see the individual substances that are mixed. You look at two bowls of ice crea
    9·1 answer
  • Using our understanding of orbits, which orbits (near or far) are moving more slowly?
    7·2 answers
  • If V is a velocity, l a length, and v a fluid property having dimensions of L2T-1, which of the following combinations are quali
    12·1 answer
  • Why should you try to avoid food containing corn sugar dextrose or sucrose
    14·2 answers
  • Which of the following best describes chemical weathering?
    10·2 answers
  • 1. A car moves 20 m/s east for 5 sec, 10m/s north for 10 sec and then 30m/s west for 5 sec. Calculate a) displacement
    13·1 answer
  • Please help me with this
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!