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3 years ago

7

A Wooden block has a mass of 0.200kg, a specific heat of 710 J (kg times degrees Celsius and is at a temperature of 20.0 degrees

Celsius. What is the blocks final temperature if it’s thermal energy increases by 2130J

1 answer:

olchik [2.2K]3 years ago

8 0

Answer:

35°C

Explanation:

q = mCΔT

2130 J = (0.200 kg) (710 J/kg/°C) (T − 20.0°C)

T = 35°C

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A 50.0 kg child stands at the rim of a merry-go-round of radius 1.50 m, rotating with an angular speed of 3.00 rad/s. (a) what i

White raven [17]

Weight of the child m = 50 kg
Radius of the merry -go-around r = 1.50 m
Angular speed w = 3.00 rad/s
(a)Child's centripetal acceleration will be a = w^2 x r = 3^2 x 1.50 => a = 9 x
1.5
Centripetal Acceleration a = 13.5m/sec^2
(b)The minimum force between her feet and the floor in circular path
Circular Path length C = 2 x 3.14 x 1.50 => c = 3 x 3.14 => C = 9.424
Time taken t = 2 x 3.14 / w => t = 6.28 / 3 => t = 2.09
Calculating velocity v = distance / time = 9.424 / 2.09 m/s => v = 4.5 m/s
Calculating force, from equation F x r = mv^2 => F = mv^2 / r => 50 x (4.5)^2

/ 1.5
F = 50 x 3 x 4.5 => F = 150 x 4.5 => F = 675 N
(c)Minimum coefficient of static friction u
F = u x m x g => u = F / m x g => u = 675/ 50 x 9.81 => 1.376
u = 1.376
Hence with the force and the friction coefficient she is likely to stay on merry-go-around.

8 0

3 years ago

A commuter train passes a passenger platform at a constant speed of 39.6 m/s. The train horn is sounded at its characteristic fr

Licemer1 [7]

Complete Question

A commuter train passes a passenger platform at a constant speed of 39.6 m/s. The train horn is sounded at its characteristic frequency of 350 Hz.

(a)

What overall change in frequency is detected by a person on the platform as the train moves from approaching to receding

(b) What wavelength is detected by a person on the platform as the train approaches?

Answer:

a

$\Delta f = 81.93 \ Hz$

b

$\lambda_1 = 0.867 \ m$

Explanation:

From the question we are told that

The speed of the train is $v_t = 39.6 m/s$

The frequency of the train horn is $f_t = 350 \ Hz$

Generally the speed of sound has a constant values of $v_s = 343 m/s$

Now according to dopplers equation when the train(source) approaches a person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as

$f_1 = f * \frac{v_s}{v_s - v_t}$

substituting values

$f_1 = 350 * \frac{343 }{343-39.6}$

$f_1 = 395.7 \ Hz$

Now according to dopplers equation when the train(source) moves away from the person on the platform(observe) then the frequency on the sound observed by the observer can be mathematically represented as

$f_2 = f * \frac{v_s}{v_s +v_t}$

substituting values

$f_2 = 350 * \frac{343}{343 + 39.6}$

$f_2 = 313.77 \ Hz$

The overall change in frequency is detected by a person on the platform as the train moves from approaching to receding is mathematically evaluated as

$\Delta f = f_1 - f_2$

$\Delta f = 395.7 - 313.77$

$\Delta f = 81.93 \ Hz$

Generally the wavelength detected by the person as the train approaches is mathematically represented as

$\lambda_1 = \frac{v}{f_1 }$

$\lambda_1 = \frac{343}{395.7 }$

$\lambda_1 = 0.867 \ m$

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4 years ago

What is an advantage of using oil instead of wind to generate electricity?

Anastaziya [24]

A is the only logical answer

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3 years ago

Two soccer players kick the same 2-kg ball at the same time in opposite directions one kicks with a force of 15 n the other kick

Illusion [34]

Because the direction of the kicks are opposite, the net force between the applied forces is their difference.
Fn = F₂ - F₁
Substituting,
Fn = 15 N - 5 N
Fn = 10 N

From Newton's second law of motion,
Fn = m x a
where m is mass and a is acceleration. Manipulating the equation so that we are able to calculate for a,
a = Fn / m

Substituting,
a = (10 N) / 2 kg
a = 5 m/s²

<em>ANSWER: 5 m/s²</em>

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3 years ago

Read 2 more answers

Match the choices below to the correct description. Drag the terms on the left to the appropriate blanks on the right. ResetHelp

Andreas93 [3]

Answer: hello the terms are missing but I have provided the answer ( the terms and matched them properly

answer :

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3 years ago