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3 years ago

8. The legs of a young man are each 0.650 meters long. What is his maximum walking speed?

Physics

1 answer:

Norma-Jean [14]3 years ago

8 0

Answer:

2.52 m/s

Explanation:

When the man takes a step, his foot is stationary while his body revolves around it. At the point when his body is directly above his foot, there will be no normal force at his maximum speed.

Sum of the forces in the radial direction:

∑F = ma

mg = m v² / r

g = v² / r

v = √(gr)

Given that r = 0.650 m:

v = √(9.8 m/s² × 0.650 m)

v = 2.52 m/s

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A generator makes electricity from _____ A. Chemical reactions B. Friction C. Kinetic energy D. Heat

coldgirl [10]

Answer:

The answer is C. Kinetic energy

Explanation:

Generators don't actually create electricity. Instead, they convert mechanical or chemical energy into electrical energy. They do this by capturing the power of motion and turning it into electrical energy by forcing electrons from the external source through an electrical circuit.

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3 years ago

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A car is stopped at a traffic light. When the light turns green at t=0, a truck with a constant speed passes the car with a 20m/

s344n2d4d5 [400]

Answer:

At $t = (70 / 3) \; {\rm s}$ (approximately $23.3 \; {\rm s}$ .)

Explanation:

Note that the acceleration of the car between $t = 0\; {\rm s}$ and $t = 20\; {\rm s}$ ( $\Delta t = 20\; {\rm s}$ ) is constant. Initial velocity of the car was $v_{0} = 0\; {\rm m\cdot s^{-1}}$ , whereas $v_{1} = 35\; {\rm m\cdot s^{-1}}$ at $t = 20\; {\rm s}\!$ . Hence, at $t = 20\; {\rm s}\!\!$ , this car would have travelled a distance of:

$\begin{aligned}x &= \frac{(v_{1} - v_{0})\, \Delta t}{2} \\ &= \frac{(35\; {\rm m\cdot s^{-1}} - 0\; {\rm m\cdot s^{-1}}) \times (20\; {\rm s})}{2} \\ &= 350\; {\rm m}\end{aligned}$ .

At $t = 20\; {\rm s}$ , the truck would have travelled a distance of $x = v\, t = 20\; {\rm m\cdot s^{-1}} \times 20\; {\rm s} = 400\; {\rm m}$ .

In other words, at $t = 20\; {\rm s}$ , the truck was $400\; {\rm m} - 350\; {\rm m} = 50\; {\rm m}$ ahead of the car. The velocity of the car is greater than that of the truck by $35\; {\rm m\cdot s^{-1}} - 20\; {\rm m\cdot s^{-1}} = 15 \; {\rm m\cdot s^{-1}}$ . It would take another $(50\; {\rm m}) / (15\; {\rm m\cdot s^{-1}}) = (10/3)\; {\rm s}$ before the car catches up with the truck.

Hence, the car would catch up with the truck at $t = (20 + (10/3))\; {\rm s} = (70 / 3)\; {\rm s}$ .

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1 year ago

During a thunderstorm, a plasma channel forms between the negatively charged clouds and the positively charged Earth, which crea

olchik [2.2K]

Electrons would likely pass through the plasma channel when the formation of a lightning takes place. Lightning is primarily caused by the formation of an ionised cloud in the atmosphere. This cloud was due to the attractions between molecules of rain drops wherein produce a negative charge.

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3 years ago

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Suppose that a meter stick is balanced at its center. A 0.24 kg mass is then positioned at the 6-cm mark. At what cm mark mus

Scilla [17]

Answer:

80.17 cm

Explanation:

Taking moments of forces about the center, the total clockwise moments is equal to the total counter clockwise moment:

Force * distance (counter clockwise) = force * distance (clockwise)

0.24 * 9.8 * (50 - 6) = 0.35 * 9.8 * (x - 50)

0.24 * 44 = 3.43x - 171.5

103.5 = 3.43x - 171.5

=> 3.43x = 103.5 + 171.5

3.43x = 275

x = 275/3.43 = 80.17 cm

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3 years ago

A truck is carrying a refrigerator as shown in the figure. The height of the refrigerator is 158.0 cm, the width is 60.0 cm. The

kirza4 [7]

In order for the refrigerator not to tip over, the maximum acceleration of 1.86 m/s² must not be exceeded.

<h3>What is acceleration?</h3>

The term acceleration has to do with the rate at which velocity changes with time.

We have to take the moments at the tipping point of rotation as follows;

Clockwise moment = Anticlockwise moment

Hence;

F₂ * 1.58 m = F₁ * 0.67 m

The weight at half the width= 30 cm or 0.3 m

Height of refrigerator = 158 cm 0r 1.58 cm

Then;

m * a * 1.58 = m * 9.81 * 0.30

a = 1.86 m/s²

In order for the refrigerator not to tip over, the maximum acceleration of 1.86 m/s² must not be exceeded.

Learn more about acceleration: brainly.com/question/14344386

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2 years ago