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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

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nikklg [1K]

Answer:

16.2 m/s

Explanation:

2ad=Vf^2-Vi^2

2 (1.5) (40) = Vf^2 -(12)^2

Vf= 16.2 m/s

4 0
2 years ago
Baking cake is what a physical or chemical change
xenn [34]

Answer:

It's a chemical change.

Explanation:

The ingredients will react together once mixed and heated. Also the ingredients can not be pulled apart.

8 0
3 years ago
If you quadruple the temperature of a black body, by what factor will the total energy radiated per second per square meter incr
arlik [135]

<u>In modern physics</u>, as it was called "Stefan-Boltzmann law", the total energy radiated per unit surface area of a black body is directly proportional to the fourth power of the black body's temperature T

as:

P\alpha T^4

where: P is the power (total energy radiated per second per square meter) and T is the temperature of a black body.

then we can make a ratio between the state of before quadruple (with subscript 1) and after (with subscript 2) as:

\frac{P_{1} }{P_{2} } =\frac{T_{1}^4 }{T_{2}^4}

As

T_{2}=4T_{1}

Then

\frac{P_{1} }{P_{2} } =\frac{T_{1}^4 }{(4T_{1})^4}

then

P_{2}=256*P_{1}

  • The factor will the total energy radiated per second per square meter increase = 256
5 0
3 years ago
Can y’all help me with 5 plsssss
Alona [7]

Answer:

Bar graph

Explanation:

each day collects data so a bar graph would work.

4 0
2 years ago
Read 2 more answers
You guys cant answer a dam question I ask it fricking 6th grade questions
nexus9112 [7]

Answer:

calm down please its not that serious maybe no one saw it yet

Explanation:

7 0
3 years ago
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