2 years ago

A cyclist and his bicycle have a combined mass of 85 kg. If he is moving at

Physics

1 answer:

Elden [556K]2 years ago

6 0

Answer:

211.2 kg:m/s

Explanation:

Mark brainily

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A carpenter is driving a 15.0-g steel nail into a board. His 1.00-kg hammer is moving at 8.50 m/s when it strikes the nail. Half

bekas [8.4K]

Answer: The increase in temperature of the nail after the three blows is 8.0636 Kelvins. The correct option is (d).

Explanation:

Kinetic energy of the hammer ,K.E.=

$\frac{1}{2}mv^2=\frac{1}{2}1.00 kg\times (8.50 m/s)^2=36.125 J$

Half of the kinetic energy of the hammer is transformed into heat in the nail.

Energy transferred to the nail in one blow =

$\frac{1}{2}K.E.=\frac{1}{2}\times 36.125 J=18.0625 J$

Total energy transferred after 3 blows,Q = $3\times 18.0625 J=54.1875 J$

Mass of the nail = 15 g = 0.015 kg

Change in temperature = $\Delta T$

Specif heat of the steel = c = 448 J/kg K

$Q=mc\Delta T$

$54.1875 J=0.015 kg\times 448 J/kg K\times \Delta T$

$\Delta T=8.0636 K\approx 8.1 K$

The increase in temperature of the nail after the three blows is 8.1 Kelvins.Hence, correct option is (d).

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2 years ago

A starter pistol is fired 150m away from the spectators who hear the gun 0.5s after they see it fired. How fast does sound trave

Natali [406]

Answer:

300m/s

Explanation:

speed = distance/time

150/0.5

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2 years ago

What ia the law of convesation of energy

Free_Kalibri [48]

In physics and chemistry, the law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. This law means that energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another.

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3 years ago

A speaker emits sound waves in all directions, and at a distance of 28 m from it the intensity level is 73 db. What is the total

Oduvanchick [21]

Answer:

P=0.197 Watt

Explanation:

Given That

B=73dB

Io= 1 * 10^-12

$I=Io * 10^{\frac{B}{10} } \\I=2 * 10^{-5} Wm^{-2} \\A=4 * pi * r^{2}\\ A=9852.03 m^{2}\\ Power= I * A\\P= 0.197 Watt$