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3 years ago

Sam, whose mass is 60 Kg, is riding on a 5.0 kg sled initially traveling at 8.0 m/s. He

Physics

1 answer:

umka2103 [35]3 years ago

8 0

<h3>Answer: 130 newtons</h3>

===============================================================

Explanation:

We'll need the acceleration first.

The initial speed (let's call that Vi) is 8.0 m/s
The final speed (Vf) is 0 m/s since Sam comes to a complete stop at the end.
This happens over a duration of t = 4.0 seconds

The acceleration is equal to the change in speed over change in time

a = acceleration

a = (change in speed)/(change in time)

a = (Vf - Vi)/(4 seconds)

a = (0 - 8.0)/4

a = -8/4

a = -2

The acceleration is -2 m/s^2, meaning that Sam slows down by 2 m/s every second. Negative accelerations are often associated with slowing down. The term "deceleration" can be used here.

Here's a further break down of Sam's speeds at the four points of interest

At 0 seconds, he's going 8 m/s
At the 1 second mark, he's slowing down to 8-2 = 6 m/s
At the 2 second mark, he's now at 6-2 = 4 m/s
At the 3 second mark, he's at 4-2 = 2 m/s
Finally, at the 4 second mark, he's at 2-2 = 0 m/s

Next, we'll apply Newton's Second Law of motion

F = m*a

where,

F = force applied
m = mass
a = acceleration

We just found the acceleration, and the mass is fairly easy as all we need to do is add Sam's mass with the sled's mass to get 60+5.0 = 65 kg

So the force applied must be:

F = m*a

F = 65*(-2)

F = -130 newtons

This force is negative to indicate it's pushing against the sled's momentum to slow Sam down.

The magnitude of this force is |F| = |-130| = 130 newtons

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Sherry and Ellen are talking about the factors that affect light scattering in the atmosphere. Sherry says one factor is the len

Delvig [45]

Sherry who says one factor is the length of the path of sunlight is correct.

<h3>Factors affecting light scattering</h3>

There are two main factors which affects light scattering, and they include the following;

the size of the particles
wavelength of the light

length of the path of sunlight is equivalent to wavelength of the light.

Thus, we can conclude that Sherry who says one factor is the length of the path of sunlight is correct.

Learn more about light scattering here: brainly.com/question/1381101

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2 years ago

A 73-kg person in a moving car stops during a car collision in a distance of 0.80 m . The stopping force that the air bag exerts

fredd [130]

Answer:

v₀ = 13.24 m / s

Explanation:

Let's use Newton's second law to find the average acceleration during the crash

F = m a

. a = F / m

a = 8000/73

a = 109.59 m / s²

Now we can use the kinematic equations to find the initial velocity, since when the velocity stops it is zero (v = 0)

v² = v₀² - 2 a x

v₀² = 2 a x

v₀ = √ 2 a x

v₀ = √ (2 109.59 0.80)

v₀ = 13.24 m / s

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4 years ago

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Can anyone explain<br>if knows

Aleks [24]

Answer:

Sry I’m just trying to get my points :(

Explanation:

Better luck nest time I would help if I was smart enough but currently I’m as d u m b as a rock...

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3 years ago

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An object with a mass of 0. 25 kg is undergoing simple harmonic motion at the end of a vertical spring with a spring constant, k

skelet666 [1.2K]

Answer:

1) The amplitude of the motion is approximately 0.274 meters.

2) The total energy of the object at any point of its motion is 16.892 joules.

Explanation:

1) An object under simple harmonic motion is conservative, since there is no dissipative forces acting during motion (i.e. friction, air viscosity). The amplitude of the motion can be found easily by Principle of Energy Conservation by the fact that maximum elastic potential energy ( $U_{e}$ ), in joules, is equal to maximum translational kinetic energy ( $K$ ), in joules:

$U_{e} = K$

$\frac{1}{2}\cdot k \cdot A^{2} = \frac{1}{2}\cdot m \cdot v^{2}$ (1)

Where:

$k$ - Spring constant, in newtons per meter.

$A$ - Amplitude, in meters.

$m$ - Object mass, in kilograms.

$v$ - Speed of the object at equilibrium, in meters per second.

If we know that $k = 450\,\frac{N}{m}$ , $m = 0.25\,kg$ and $v = 0.3\,\frac{m}{s}$ , then the amplitude of the motion is:

$\frac{1}{2}\cdot k \cdot A^{2} = \frac{1}{2}\cdot m \cdot v^{2}$

$k\cdot A^{2} = m\cdot v^{2}$

$A = v\cdot \sqrt{\frac{m}{k} }$

$A = \left(0.3\,\frac{m}{s} \right)\cdot \sqrt{\frac{0.25\,kg}{0.3\,\frac{m}{s} } }$

$A \approx 0.274\,m$

The amplitude of the motion is approximately 0.274 meters.

2) The total energy of the object ( $E$ ), in joules, is found either by maximum elastic potential energy or by maximum translational kinetic energy, that is: ( $k = 450\,\frac{N}{m}$ , $A \approx 0.274\,m$ )

$E = U_{e}$

$E = \frac{1}{2}\cdot k\cdot A^{2}$

$E = \frac{1}{2}\cdot \left(450\,\frac{N}{m} \right) \cdot (0.274\,m)^{2}$

$E = 16.892\,J$

The total energy of the object at any point of its motion is 16.892 joules.

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3 years ago

Forecast error is found by subtracting the forecast from the actual demand for a given period. True or False

kap26 [50]

Answer:

True

Explanation:

Forecast error can be referred to as the deviation of the actual demand from the forecasted or predicted demand.

In other words, it is the difference between the actual or real and the predicted or forecast value of a time series.

From the definition, we understand that forecast error is all about how much is the difference between what's is been forecasted and the actual value.

Mathematically,

Forecast Error = Actual Value of Demand - Forecasted Value of Demand.

Irrespective of whether the actual prediction is smaller or not; on a more standard term, it is calculated as follows

Forecast Error = ABS (Actual – Forecast)

Where ABS = the absolute value of....

And it always returns a positive value of the expression in brackets

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3 years ago

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