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2 years ago

What is the average acceleration of a car that is initially at rest at a stoplight and then accelerates to 24 m/s in 9.4 s?

Physics

2 answers:

andrezito [222]2 years ago

8 0

brainly.com/question/11542618?answering=true&answeringSource=greatJob%2FquestionPage

topjm [15]2 years ago

5 0

Answer:

B) a= 2.6 m/s²

Explanation:

Conceptual analysis:

Because the car moves with uniformly accelerated movement, we apply the following formula :

vf= v₀+a*t Formula (1)

Where:

t : time in seconds (s)

v₀: initial speed in m/s

vf: final speed in m/s

a: acceleration in m/s²

Known Data

v₀=0

vf = 24 m/s

t= 9.4

Development problem

We replace the data in the formula (1)

vf= v₀+a*t

24 m/s = 0 + a*9.4s

a = (24 m/s) / (9.4s)

a= 2.6 m/s²

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A man climbs a ladder. Which two quantities can be used to calculate the energy stored of the man at the top of the ladder.

Dvinal [7]

Answer:The answer must be The weight of the man and the vertical distance moved.

Explanation: you calculate it by the force you applied times the distance you moved

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2 years ago

Max and Jimmy want to jump on a trampoline. Max begins jumping in a steady pattern, making small waves in the trampoline. Jimmy

mylen [45]

Answer:

x_total = (A + B) cos (wt + Ф)

we have the sum of the two waves in a phase movement

Explanation:

In this case we can see that the first boy Max when he enters the trampoline and jumps creates a harmonic movement, with a given frequency. When the second boy Jimmy enters the trampoline and begins to jump he also creates a harmonic movement. If the frequency of the two movements is the same and they are in phase we have a resonant process, where the amplitude of the movement increases significantly.

Max

x₁ = A cos (wt + Ф)

Jimmy

x₂ = B cos (wt + Ф)

total movement

x_total = (A + B) cos (wt + Ф)

Therefore we have the sum of the two waves in a phase movement

8 0

2 years ago

A boy on a bicycle approaches a brick wall as he sounds his horn at a frequency 400 hz. the sound he hears reflected back from t

Mashutka [201]

As the question is about changing in frequency of a wave for an observer who is moving relative to the wave source, the concept that should come to our minds is "Doppler's effect."

Now the general formula of the Doppler's effect is:
$f = (\frac{g + v_{r}}{g + v_{s}})f_{o}$ -- (A)

Note: We do not need to worry about the signs, as everything is moving towards each other. If something/somebody were moving away, we would have the negative sign. However, in this problem it is not the issue.

Where,
g = Speed of sound = 340m/s.
$v_{r}$ = Velocity of the receiver/observer relative to the medium = ?.
$v_{s}$ = Velocity of the source with respect to medium = 0 m/s.
$f_{o}$ = Frequency emitted from source = 400 Hz.
$f$ = Observed frequency = 408Hz.

Plug-in the above values in the equation (A), you would get:

$408 = ( \frac{340 + v_{r}}{340 + 0})*400$

$\frac{408}{400} = \frac{340 + v_{r}}{340}$

Solving above would give you,
$v_{r}$ = 6.8 m/s

The correct answer = 6.8m/s

7 0

2 years ago

A rocket exhausts fuel with a velocity of 1500m/s, relative to the rocket. It starts from rest in outer space with fuel comprisi

babunello [35]

Answer:

v= 2413.5 m/s

Explanation:

maximum change of speed of rocket

=(initial exhaust velocity)×ln [(initialmass/finalmass)]

let initial mass= m

final mass = m-m(4/5) = m/5

[since the 80% of mass which is fuel is exhausted]

V-0 = 1500 ln (1/0.2)

V= 1500×1.609 = 2413.5 m/s

therefore, its exhaust speed v= 2413.5 m/s

4 0

2 years ago

Read 2 more answers

If the mass of a material is 45 grams and the volume of the material is 8 cm^3, what would the density of the material be?

Svet_ta [14]

The density of the substance is the ratio of its mass over the space it occupies. In mathematical equation, this can be expressed as,

ρ = m / v

where ρ is density, m is mass, and v is volume.

Substituting the known values from the given,

ρ = (45 g) / (8 cm³)

ρ = 5.625 g/cm³

<em>ANSWER: 5.625 g/cm³</em>

3 0

2 years ago