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3 years ago

Explain why the tip of a sewing needle is sharp

1 answer:

3 0

Because of its Sharp tip the needle is able to put the force on a very small area of the cloth, producing a large pressure sufficient enough to pierce the cloth being stitched and allow to stitch the thread in and pull it out.

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A boy throws a ball and accidentally breaks a window. The momentum of the ball and all the pieces of glass taken together after

Aleks [24]

When a boy throws a ball and accidentally breaks a window, the momentum of the ball and all the pieces of glass taken together after the collision is THE SAME as the momentum of the ball before the collision

hope this helps

6 0

3 years ago

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Suppose you are drinking root beer from a conical paper cup. The cup has a diameter of 10 centimeters and a depth of 13 centimet

sveta [45]

Answer:

The level of the root beer is dropping at a rate of 0.08603 cm/s.

Explanation:

The volume of the cone is :

$V=\frac {1}{3}\times \pi\times r^2\times h$

Where, V is the volume of the cone

r is the radius of the cone

h is the height of the cone

The ratio of the radius and the height remains constant in overall the cone.

Thus, given that, r = d / 2 = 10 / 2 cm = 5 cm

h = 13 cm

r / h = 5 / 13

r = {5 / 13} h

$V=\frac {1}{3}\times \frac {22}{7}\times ({{{\frac {5}{13}\times h}}})^2\times h$

$V=\frac {550}{3549}\times h^3$

Also differentiating the expression of volume w.r.t. time as:

$\frac {dV}{dt}=\frac {550}{3549}\times 3\times h^2\times \frac {dh}{dt}$

Given: $\frac {dV}{dt}$ = -4 cm³/sec (negative sign to show leaving)

h = 10 cm

So,

$-4=\frac{550}{3549}\times 3\times {10}^2\times \frac {dh}{dt}$

$\frac{55000}{1183}\times \frac {dh}{dt}=-4$

$\frac {dh}{dt}=-0.08603\ cm/s$

<u>The level of the root beer is dropping at a rate of 0.08603 cm/s.</u>

3 0

3 years ago

To a stationary observer, a bus moves north with a speed of 10 m/s. A man inside walks toward the back of the bus with a speed o

Rudiy27

9.6m/s - apex .........................

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3 years ago

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What is the mechanical advantage of a pulley?

STatiana [176]

<span>the mechanical advantage of a pulley is 1.0

</span>

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3 years ago

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Which statement correctly defines power?

Anna007 [38]

Answer:

$Power=V\, I$ which corresponds to the second option shown: "voltage times amperage"

Explanation:

The electric power is the work done to move a charge Q across a given difference of potential V per unit of time.

Since such electrical work is the product of the potential difference V times the charge that moves through that potential, and this work is to be calculated by the unit of time, we need to divide the product by time (t) which leads to the following final simple equation:

$Power=\frac{V\,Q}{t} =V\,\frac{Q}{t} = V\, I$

Notice that we replaced the quotient representing charge per unit of time (Q/t) by the actual current running through the circuit.

This corresponds to the second option shown in the question: "Voltage times amperage".

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3 years ago