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mamaluj [8]
2 years ago
14

A bicycle racer rides from a starting marker to a turnaround marker at 10 m/s. She then rides back along the same route from the

turnaround marker to the starting marker at 16 m/s. What is her average speed for the whole race?
Physics
1 answer:
vitfil [10]2 years ago
8 0

Answer:

12.31 m/s

Explanation:

If we recall from the previous knowledge we had about speed,

we will know that:

speed = distance/ time.

As such:

The average speed of the rider bicycle is

average speed = total distance/ total time

Mathematically, it can be computed as:

v_{avg} = \dfrac{d+d}{\dfrac{d}{v_1}+ \dfrac{d}{v_2}}

v_{avg} = \dfrac{2d}{\dfrac{d}{10 \ m/s}+ \dfrac{d}{16 \ m/s}}

v_{avg} = \dfrac{2}{\dfrac{1}{10 \ m/s}+ \dfrac{1}{16 \ m/s}}

v_{avg} = \dfrac{2}{\dfrac{13}{80 \ m/s}}

\mathbf{v_{avg} =12.31 \ m/s}

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3 0
3 years ago
Read 2 more answers
Otion
Scorpion4ik [409]

Answer:

SKID

Explanation:

In general, airplane tracks are flat, they do not have cant, consequently the friction force is what keeps the bicycle in the circle.

Let's use Newton's second law, let's set a reference frame with the horizontal x-axis and the vertical y-axis.

Y axis y

     N- W = 0

     N = W

X axis (radial)

        fr = m a

the acceleration in the curve is centripetal

         a = \frac{v^2}{r}

the friction force has the expression

        fr = μ N

we substitute

       μ mg = m v²/r

       v = \sqrt{\mu g r}

we calculate

      v = \sqrt{0.1 \ 9.8 \ 3}

      v = 1,715 m / s

to compare with the cyclist's speed let's reduce to the SI system

        v₀ = 18 km / h (1000 m / 1 km) (1 h / 3600 s) = 5 m / s

We can see that the speed that the cyclist is carrying is greater than the speed that the curve can take, therefore the cyclist will SKID

5 0
3 years ago
You push your couch a distance of 3.9 m across the living room floor with a horizontal force of 220.0 n. the force of friction i
Mrac [35]

The general formula to calculate the work is:

W=Fd \cos \theta

where F is the force, d is the displacement of the couch, and \theta is the angle between the direction of the force and the displacement. Let's apply this formula to the different parts of the problem.


(a) Work done by you: in this case, the force applied is parallel to the displacement of the couch, so \theta=0^{\circ} and \cos \theta=1, therefore the work is just equal to the product between the horizontal force you apply to push the couch and the distance the couch has been moved:

W=Fd=(220.0 N)(3.9 m)=858 J


(b) work done by the frictional force: the frictional force has opposite direction to the displacement, therefore \theta=180^{\circ} and \cos \theta=-1. Therefore, we must include a negative sign when we calculate the work done by the frictional force:

W=-Fd=-(144.0 N)(3.9 m)=-561.6 J


(c) The work done by gravity is zero. In fact, gravity (which points downwards) is perpendicular to the displacement of the couch (which is horizontal), therefore \theta=90^{\circ} and \cos \theta=0: this means

W=0.


(d) Work done by the net force:

The net force is the difference between the horizontal force applied by you and the frictional force:

F=220 N-144 N=76 N

And the net force is in the same direction of the displacement, so \theta=0^{\circ} and \cos \theta=1 and the work done is

W=Fd=(76 N)(3.9 m)=296.4 J


4 0
3 years ago
Question 3 of 15
omeli [17]

Answer:

B) Degrees

Explanation:

The directions of the vectors are often defined in terms of due East, due North, due West and due South. A direction exactly in between of North and East can be described as Northeast, similarly we can describe directions in terms of Northwest, Southeast and South west.

From these, the direction of a vector can be easily expressed in degrees, which is measured counter clockwise about its tail from due East. Considering that we can say that East is at 0° , North is at 90° , West is at 180 and South is at 270° counter clockwise rotation from due East.

So, we know that the direction of a vector lying somewhere between due East i.e 0° and due North i.e 90°, will be measured in degrees, which will have a value between 0°-90°

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Why doe cups break in the winter?
eimsori [14]

Answer: Glass may break at low temperatures, but this is because the contents freeze and their expansion cause the glass to crack (if the cap does not come off). ... Hot temperatures can cause the glass to break when the bottle is subject to excessive thermal variations. hope this helps can u give me brainliest

Explanation:

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