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3 years ago

Which of the following is not an example of doing work?

Physics

2 answers:

Tju [1.3M]3 years ago

5 0

Maybe holding a tray in the cafeteria line

Whitepunk [10]3 years ago

5 0

Answer:

A. Holding a tray in the cafeteria line!

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A cyclist going downhill is accelerating at 1. 2 m/s2. If the final velocity of the cyclist is 16 m/s after 10 seconds, what is

mel-nik [20]

Answer:

$\boxed {\boxed {\sf v_i= 4 \ m/s}}$

Explanation:

We are asked to find the cyclist's initial velocity. We are given the acceleration, final velocity, and time, so we will use the following kinematic equation.

$v_f= v_i + at$

The cyclist is acceleration at 1.2 meters per second squared. After 10 seconds, the velocity is 16 meters per second.

$v_f$ = 16 m/s
a= 1.2 m/s²
t= 10 s

Substitute the values into the formula.

$16 \ m/s = v_i + (1.2 \ m/s^2)(10 \ s)$

Multiply.

$16 \ m/s = v_i + (1.2 \ m/s^2 * 10 \ s)$

$16 \ m/s = v_i + 12 \ m/s$

We are solving for the initial velocity, so we must isolate the variable $v_i$ . Subtract 12 meters per second from both sides of the equation.

$16 \ m/s - 12 \ m/s = v_i + 12 \ m/s -12 \ m/s$

$4 \ m/s = v_i$

The cyclist's initial velocity is <u>4 meters per second.</u>

6 0

3 years ago

Exactly one pound of bread dough is placed in a baking tin. the dough is cooked in an oven at 350 °f releasing a wonderful aroma

Sladkaya [172]

The mass of the baked loaf will be less than the original dough. In making dough for bread, we have ingredients that are liquid such as water, melted butter, food flavoring, etc. All of this liquid ingredients mixed on the dough will definitely turn into vapor. This vapor is responsible for releasing of the aroma of the freshly baked bread.

7 0

3 years ago

A solenoid 50-cm long with a radius of 5.0 cm has 800 turns. You find that it carries a current of 10 A. The magnetic flux throu

ioda

Answer:

126 mWb

Explanation:

Given that:

length (L) = 50 cm = 0.5 m, radius (r) = 5 cm = 0.05 m, current (I) = 10 A, number of turns (N) = 800 turns.

We assume that the magnetic field in the solenoid is constant.

The magnetic flux is given as:

$\phi_m=NBAcos(\theta)\\Where\ B\ is\ the\ magnetic\ field\ density,A\ is \ the\ area.\\But\ B =\mu_onI.\ n \ is\ the\ number\ of\ turns\ per\ unit \ length=N/L\\Therefore,B=\frac{\mu_oNI}{L} \\substituting\ the\ value\ of\ B\ in\ the\ equation: \\\phi_m=\frac{NAcos(\theta)*\mu_oNI}{L} .\ But \ \theta=0,cos(\theta)=1\ and\ A=\pi r^2\\ \phi_m=\frac{N^2\pi r^2\mu_oI}{L} \\Substituting\ values:\\\phi_m=\frac{800^2*(\pi*0.05^2)*(4\pi*10^{-7})*10}{0.5}=0.126\ Wb=126\ mWb$

8 0

3 years ago

Is mass is 88.2 and height of distance is 25m, how do you find speed?

Natasha_Volkova [10]

Answer:

The velocity will be v = 22.1[m/s]

Explanation:

We can solve this problem by using the principle of energy conservation, where potential energy is converted to kinetic energy. For this problem we will take the point with maximum potential energy when the body is 25 [m] high. By the time the height is zero, the potential energy will have been transformed into kinetic energy, and we can find the velocity of the body.

$Ep = m*g*h\\where:\\m = mass = 88.2[kg]\\h = elevation = 25[m]\\g = gravity = 9.81 [m/s^2]\\Ep = 88.2*25*9.81 = 21631.05[J]\\$

Now we know that the energy will be transformed.

$Ek=Ep\\Ek=0.5*m*v^{2} \\where:\\v=velocity [m/s]\\v=\sqrt{\frac{Ek}{0.5*m} } \\v=\sqrt{\frac{21631.05}{0.5*88.2} } \\v=22.14[m/s]$

4 0

3 years ago

Water waves that you might see at the beach move in circular or elliptical paths. What type of mechanical waves are water waves?

vazorg [7]

To find:

Which type of mechanical wave is a water wave?

Explanation:

The water wave is a combination of longitudinal and transverse waves. They are a type of wave called surface waves. The surface waves are the waves that transmit energy in the interface between two mediums.

Final answer:

Thus the correct answer is option C.

5 0

1 year ago