2 years ago

Which force below acts at 90 degrees and is applied by a surface/wall to an object.

Physics

1 answer:

Molodets [167]2 years ago

4 0

Answer:

B. normal

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1. An excited lithium atom emits a red light with wavelength a = 671nm. What is the corresponding photon energy? hc (6.63 x 10-3

Rudiy27

Answer:

E = 2,964 10⁻¹⁹ J

Explanation:

The energy of the photons is given by the Planck relation

E = h f

the speed of light is related to wavelength and frequency

c = λ f

we substitute

E = h c /λ

let's reduce the magnitude to the SI system

λ = 671 nm = 671 10⁻⁹ m

let's calculate

E = 6.63 10⁻³⁴ 3 10⁸ /671 10⁻⁹

E = 2,964 10⁻¹⁹ J

6 0

2 years ago

A woman was recently given the opportunity to ride in a porsche race car on their test in Hapeville, Georgia. Below is a graph o

Zinaida [17]

Answer:

During the segments B - C and D - E, the car stopped since the y axis is the distance and the distance stayed the same in between those segments.

For a simpler answer, the flat horizontal lines on the graph are the times when the car was stopped.

6 0

2 years ago

From a vantage point very close to the track at a stock car race, you hear the sound emitted by a moving car. You detect a frequ

V125BC [204]

Answer:

55.8 m/s

Explanation:

$f$ = Actual frequency of sound emitted by car

$f'$ = frequency observed when the car moves = $(0.86)f$

$V$ = Speed of sound = 343 m/s

$v$ = Speed of car

Frequency observed is given as

$f' = \frac{Vf}{V+v}$

$(0.86) = \frac{(343)}{343 + v}\\(0.86) = \frac{(343)}{343 + v}\\294.98 + (0.86) v = 343 \\v = 55.8 ms^{-1}$

6 0

2 years ago

Determine the approximate force (N) used to pull a sled up a 400 m hill using 1900 J of work.

Sergeu [11.5K]

The work done to pull the sled up to the hill is given by
$W=Fd$
where
F is the intensity of the force
d is the distance where the force is applied.

In our problem, the work done is $W=1900 J$ and the distance through which the force is applied is $d=400 m$ , so we can calculate the average force by re-arranging the previous equation and by using these data:
$F= \frac{W}{d}= \frac{1900 J}{400 m} = 4.75 N \sim 5 N$

4 0

3 years ago

What is an independent or manipulated variable?

Paha777 [63]

Is the variable you change, independent, I, something I change.

5 0

3 years ago