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3 years ago

A car is moving with a speed of 15 ms. How long does it take to cover a distanceof 1.2 km?

Physics

1 answer:

fgiga [73]3 years ago

8 0

Answer: 80 s

Explanation:

Speed is expressed in v= d/t, derive the equation so we can have time.

First conert km into meters to cancel out both units and only seconds will remain.

1.2 km x 1000m/ 1km = 1200 m

t = 1200 m /15 m/s = 80 s

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3 years ago

A force of 333 N is applied 33 cm from the pivot point. What is the maximum torque of this situation

exis [7]

Answer: 109.89 Nm

Explanation:

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3 years ago

Calculate the efficiency of a machine if the input work is 200J and the output work is 150J.

lidiya [134]

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3 years ago

A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from t

marishachu [46]

Answer:

The impact occured at a distance of 2478.585 meters from the person.

Explanation:

(After some research on web, we conclude that problem is not incomplete) The element "Part A" may lead to the false idea that question is incomplete. Correct form is presented below:

<em>A person, with his ear to the ground, sees a huge stone strike the concrete pavement. A moment later two sounds are heard from the impact: one travels in the air and the other in the concrete, and they are 6.4 seconds apart. How far away did the impact occur? (Sound speed in the air: 343 meters per second, sound speed in concrete: 3000 meters per second)</em>

Sound is a manifestation of mechanical waves, which needs a medium to propagate themselves. Depending on the material, sound will take more or less time to travel a given distance. From statement, we know this time difference between air and concrete ( $\Delta t$ ), in seconds:

$\Delta t = t_{A}-t_{C}$ (1)

Where:

$t_{C}$ - Time spent by the sound in concrete, in seconds.

$t_{A}$ - Time spent by the sound in the air, in seconds.

By suposing that sound travels the same distance and at constant speed in both materials, we have the following expression:

$\Delta t = \frac{x}{v_{A}}-\frac{x}{v_{C}}$

$\Delta t = x\cdot \left(\frac{1}{v_{A}}-\frac{1}{v_{C}} \right)$

$x = \frac{\Delta t}{\frac{1}{v_{A}}-\frac{1}{v_{C}} }$ (2)

Where:

$v_{C}$ - Speed of the sound in concrete, in meters per second.

$v_{A}$ - Speed of the sound in the air, in meters per second.

$x$ - Distance traveled by the sound, in meters.

If we know that $\Delta t = 6.4\,s$ , $v_{C} = 3000\,\frac{m}{s}$ and $v_{A} = 343\,\frac{m}{s}$ , then the distance travelled by the sound is:

$x = \frac{\Delta t}{\frac{1}{v_{A}}-\frac{1}{v_{C}} }$

$x = 2478.585\,m$

The impact occured at a distance of 2478.585 meters from the person.

7 0

3 years ago

HELP PLEASE!!

sweet-ann [11.9K]

Answer:

C. More of the heat is transferred to the kinetic energy of the copper atoms than to the kinetic energy of the water molecules.

Explanation:

Both equal masses of water and copper were heated at the same temperature. Since copper is a good conductor of heat compared to water, its absorbs more heat. Which in-turn increases the rate of vibrations of the atoms in the copper mass, thus increasing their kinetic energy.

In the case of water, its molecules displaces one another after being heated to a higher temperature compared to neighboring molecules. So that the heated molecule becomes less dense and floats to the surface of water.

This property of copper makes it to be heated to a higher final temperature than the water.

6 0

3 years ago

A car is moving with a speed of 15 ms. How long does it take to cover a distanceof 1.2 km?​

A car is moving with a speed of 15 ms. How long does it take to cover a distanceof 1.2 km?