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3 years ago

Dave is walking from the back of a train to the front of the train at a rate of 6

1 answer:

monitta3 years ago

6 0

48 km/hr. Because the trains speed remains constant and is unaffected to Dave’s speed and Dave’s speed will remain relative to the trains speed. Taken that, when Dave is moving 0 km/hr he is moving at 42km/hr. So his speed must only add to that.

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A manufacturer supplies plastic cups that are placed under the legs of the chair

777dan777 [17]

A manufacturer supplies plastic cups that are placed under the legs of the chair. The manufacturer's claim is that there will be no marks of chair due to pushing or pulling on the floor.

<h3>Who is a manufacturer?</h3>

A manufacturer is a person who converts his idea of developing and constructing any item using some set of machines.

A manufacturer supplies plastic cups that are placed under the legs of the chair.

When there is a relative motion between two objects, friction force causes the opposition to this motion. Between chair and floor, there will be high magnitude of force. But if we insert plastic cups in the legs of chair, then the friction between cup and floor will be less. This keeps the floor protected form any scratches.

Learn more about manufacturer.

brainly.com/question/15494518

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6 0

2 years ago

A ring made of gold is heated and then hammered into a flat, coin-like shape. Is this a physical change? Explain.

Tamiku [17]

Yes. a physical change is only modifying the structure of it.

a chemical change is permanently changing something.

cutting cheese into slices is a physical change

cooking an egg is a chemical change

7 0

3 years ago

Read 2 more answers

A tuba may be treated like a tube closed at one end. If a tuba has a fundamental frequency of 88.4 Hz, determine the first three

yulyashka [42]

Answer with Explanation:

We are given that

Fundamental frequency,f=88.4 Hz

Speed of sound,v=343 m/s

We have to find the first three overtones.

Tube is closed

The overtone of closed pipe is equal to odd number of fundamental frequency.

Therefore, the overtone of tuba

$f'=nf$

Where n=3,5,7,..

Substitute n=3

$f'=3\times 88.4=265.2Hz$

For second overtone

$f'=5\times 88.4=442Hz$

For third overtone

$f'=7\times 88.4=618.8Hz$

4 0

3 years ago

According to the rule of 72 and about how many years will $78 be worth $39 if the rate of inflation is 5.8%

Monica [59]

The answer is 12.4 years

3 0

3 years ago

Read 2 more answers

A box is placed on a conveyor belt that moves with a constant speed of 1.05 m/s. The coefficient of kinetic friction between the

sveticcg [70]

Answer:

The box stops in 0.139 seconds, after moving 7.29cm (0.0729m) backwards relative to the belt.

Explanation:

As the box is initially at rest relative to the earth, it is moving backwards with a speed of 1.05m/s relative to the belt. Then, the frictional force acts on the box to make it stop relative to the belt. So, we first have to write the equations of motion of the box in each axis:

$x: f_k=ma\implies a=\frac{f_k}{m} \\\\y: N-mg=0\implies N=mg$

Since the frictional force $f_k$ is equal to $f_k=\mu_k N=\mu_k mg$ , then we have that the acceleration is:

$a=\frac{\mu_k mg}{m}=\mu_k g$

Now, from the definition of acceleration we get:

$a=\frac{v-v_0}{t}\implies t=\frac{v-v_0}{a}$

And, as the final velocity is zero because the box gets to a stop, we have:

$t=-\frac{v_0}{a}=-\frac{v_0}{\mu_k g}$

(Don't worry about the negative sign. It will disappear because the initial velocity is also negative, since we take the box initially moving backwards)

Then, plugging in the given values, we calculate the time:

$t=-\frac{(-1.05m/s)}{0.770(9.81m/s^{2})}=0.139s$

In words, the time the box takes to stop sliding relative to the belt is 0.139s.

The displacement of the box in this time, is given by the kinematics formula:

$v^{2}=v_0^{2}+2ax\implies x=-\frac{v_0^{2}}{2\mu_kg}$

Finally, we calculate the displacement:

$x=-\frac{(1.05m/s)^{2} }{2(0.770)(9.81m/s^2)}=-0.0729m=-7.29cm$

This means that the box moves 7.29cm backwards relative to the belt.

4 0

3 years ago