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stiks02
1 month ago
6

Rosa studies the position-time graph of two race cars. A graph titled Position versus Time shows time in hours on the x axis, nu

mbered 0 to 5, position in kilometers on the y axis, numbered 0 to 50. The graph has two straight lines, one from point (0, 20) up to (2.8, 50), the second line starts at the origin and goes to point (5, 20). Rosa concludes that truck X has a greater velocity than truck Y, and that truck Y had a head start. She also concluded that the graph shows both trucks moving at a constant velocity and that neither truck changes direction. Which statement best describes Rosa’s error?
A Both trucks change direction after they start moving.
B Truck X had a head start, not truck Y.
C Truck Y has a greater velocity than truck X.
D The trucks are not traveling at constant velocities.
Physics
2 answers:
Sav [3.1K]1 month ago
5 0

Answer:

B. Truck X was ahead, not truck Y.

Explanation:

Let's analyze the information provided.

Truck X moved from the point (0,20) to (2.8,50). This indicates that it began at the 20th kilometer and reached 50 km in 2.8 hours. Thus, its speed is v1 = (s2 - s1) / t

v1 = (50 - 20) / 2.8

v1 = 10.7 km/h

Given that it started from the 20th km, it indeed had a head start. Since the line on the graph is linear, this shows its speed was constant without any change in direction.

On the other hand, Truck Y's movement went from the origin (0,0) to (5,20), meaning it took 5 hours to travel 20 km, resulting in a speed of v2 = 20 / 5

v2 = 4 km/h

Again, the straightness of its graph line signifies it maintained a constant speed in a single direction.

Thus, it is evident that Rosa erred in her assumption that Truck Y had a head start.

Maru [3.3K]1 month ago
4 0

Answer:

The correct answer is C

Explanation:

I just completed the test and answered it correctly

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Modern wind turbines generate electricity from wind power. The large, massive blades have a large moment of inertia and carry a
Yuliya22 [3333]

Answer:

a)106.48 x 10⁵ kg.m²

b)144.97 x 10⁵ kgm² s⁻¹

Explanation:

a)Given

m = 5500 kg

l = 44 m

The moment of inertia for one blade

I= 1/3 x m l²

where m denotes the mass of the blade

l represents the length of each blade.

Substituting the necessary values, the moment of inertia for one blade is

I= 1/3 x 5500 x 44²

I= 35.49 x 10⁵ kg.m²

Total moment of inertia for 3 blades

I= 3 x 35.49 x 10⁵ kg.m²

I= 106.48 x 10⁵ kg.m²

b) The angular momentum 'L' is calculated using

L =I x ω

where,

I= the moment of inertia of the turbine i.e 106.48 x 10⁵ kg.m²

ω= angular velocity =2π f

f represents the frequency of rotation of the blade i.e 13 rpm

f = 13 rpm=>= 13 / 60 revolutions per second

ω = 2π f => 2π  x  13 / 60 rad / s

L=I x ω =>106.48 x 10⁵ x   2π  x  13 / 60

  = 144.97 x 10⁵  kgm² s⁻¹    

7 0
16 days ago
What is the gauge pressure of the water right at the point p, where the needle meets the wider chamber of the syringe? neglect t
Yuliya22 [3333]

Details that are not provided: the problem figure is included.

We can address the exercise by applying Poiseuille's law. This law indicates that for a fluid flowing in a laminar manner within a confined pipe,

\Delta P = \frac{8 \mu L Q}{\pi r^4}

where:

\Delta P represents the pressure difference across the two ends

\mu denotes the viscosity of the fluid

L signifies the length of the pipe

Q=Av indicates the volumetric flow rate, where A=\pi r^2 is the cross-sectional area of the tube and v refers to the fluid's velocity

r stands for the pipe's radius.

This law can be utilized for the needle, allowing us to compute the pressure difference between point P and the needle's end. In this scenario, we have:

\mu=0.001 Pa/s is the dynamic viscosity of water at 20^{\circ}

L=4.0 cm=0.04 m

Q=Av=\pi r^2 v= \pi (1 \cdot 10^{-3}m)^2 \cdot 10 m/s =3.14 \cdot 10^{-5} m^3/s

and r=1 mm=0.001 m

Substituting these values into the formula yields:

\Delta P = 3200 Pa

This pressure difference specifies the value between point P and the needle's termination. As the end of the needle is under atmospheric pressure, the gauge pressure at point P, relative to atmospheric pressure, is exactly 3200 Pa.

8 0
1 month ago
A square loop of wire with initial side length 10 cm is placed in a magnetic field of strength 1 T. The field is parallel to the
kicyunya [3294]

Answer:

Induced EMF is 2 x 10⁻³ volts

Explanation:

B = strength of the magnetic field aligning with the loop's axis = 1 T

\frac{dA}{dt} = area change rate of the loop = 20 cm²/s = 20 x 10⁻⁴ m²

θ = the angle formed by the magnetic field and area vector = 0

E = the induced EMF across the loop

EMF can be calculated using the formula

E = B \frac{dA}{dt}

E = (1) (20 x 10⁻⁴ )

E = 2 x 10⁻³ volts

E = 2 mV

7 0
13 days ago
Ability of the muscles to function effectively and efficiently without undue fatigue
Keith_Richards [3271]

Response:

Physical well-being

Clarification:

7 0
2 months ago
A particle moves according to a law of motion s = f(t), t ≥ 0, where t is measured in seconds and s in feet. f(t) = 0.01t4 − 0.0
serg [3582]
Since you've completed parts a and b, I will tackle part c.
For part C
To respond to this question, we must identify the zeros of the velocity function:
v(t)=0.04t^3-0.06t^2
This polynomial can be factored:
v(t)=0.04t^3-0.06t^2=t^2(0.04t-0.06)
Finding the zeros now becomes straightforward since the function equals zero when any factor is zero.
t^2=0;\\ 0.04t-0.06=0
By solving these equations, we identify our zeros:
t_1=0; t_2=\frac{3}{2}
The particle remains stationary at t=0 and t=3/2.
For part D
We must discover when the velocity function exceeds zero. We will utilize its factored form.
We will assess when each factor is greater than zero and compile the findings in the following table:
\centering \label{my-label} \begin{tabular}{lllll} Range & -\infty & 0 & 3/2 & +\infty \\ t^2 & - & + & + & + \\ 0.04t-0.06 & - & - & + & + \\ t^2 (0.04t-0.06) & + & - & + & + \end{tabular}
From the table, it's evident that our function is positive when - \infty < t and t>3/2.
This indicates the interval during which the particle moves forward.
For part E
The distance traveled can be represented as:
s(t)=0.01t^4 - 0.02t^3
We simply substitute t=12 to calculate the total distance traveled:
s(12)=0.01(12)^4 - 0.02(12)^3=172.80 ft
For part F
Acceleration is defined as the rate at which velocity changes.
We determine acceleration by deriving the velocity function concerning time.
a(t)=\frac{dv}{dt}=(0.04t^3-0.06t^2)'=0.12t^2-0.12t
To find the acceleration at 1 second, we substitute t=1s into the previous equation:
a(1)=0.12-0.12=0


7 0
1 month ago
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