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2 years ago

An old lorry is 20% efficient at converting the

Physics

1 answer:

AleksandrR [38]2 years ago

4 0

Answer:

The amount of mechanical energy produced by the old lorry when 600 Joules of chemical energy have been used by the engine, M.E. is 120 Joules

Explanation:

The question is a word problem on the relationship between energy efficiency and energy consumption

The given parameters of the old lorry are;

The chemical energy to mechanical energy conversion efficiency of the old lorry = 20%

The amount of chemical energy used by the engine = 600 joules

Let 'M.E.' represent the amount of mechanical energy produced by the old lorry, we have;

$Energy \ Efficiency = \dfrac{Energy \ produced }{Total \ Energy \ Taken \ In \ or \ Used} \times 100$

Therefore, the for the old lorry, we have;

$20\% = \dfrac{M.E. \ Produced}{600 \ Joules} \times 100$

∴ M.E. Produced = 20/100 × 600 J = 120 J

The amount of mechanical energy produced by the old lorry when 600 Joules of chemical energy have been used by the engine, M.E. = 120 Joules

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An open pipe of length 0.39m vibrates in the third harmonic with a frequency of 1400Hz. What is the distance from the center of

Gnoma [55]

Length of the pipe = 0.39 m

Third harmonic frequency = 1400 Hz

For the third harmonic:

Wavelength = $\frac{2L}{3}$

The center of the open pipe will host a node and the nearest anti - node from the center will be at the 0.25 × wavelength

Distance from center = 0.25 × wavelength

Distance = $0.25 x \frac{2L}{3}$

Plugging the value of the length of the pipe (L) = 0.39 m = 39 cm

Distance = $0.25 x \frac{2 \times 39}{3}$

Distance from the center to the nearest anti - node = 6.5 cm

Hence, the nearest distance to the anti - node from the center = 6.5 cm

So, option C is correct.

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2 years ago

(1 point) A pilot flies in a straight path for 1 hour and 30 min. She then makes a course correction, heading 10 degrees to the

kati45 [8]

Answer:

The pilot is 2214.22 miles from her starting position

Explanation:

Since the pilot is traveling at a constant speed of 635 mph, the total distance traveled can be easily found as follows:

$1stleg: d_{1} = 1.5*635 = 952.5 mi\\2ndleg: d_{2} = 2*635 = 1270 mi$

There was a 10 degrees deviation, so the angle between the trajectory of both legs is 170 degrees.

The distance we need to find is that from the start of the first leg to the end of the second leg, those three distances form a triangle and since the side we're interested in is opposite to the 170 degrees angle, we can determine its length by the law of cosines:

$d_{3}^{2} =d_{1}^{2} + d_{2}^{2} -2*d_{1}*d_{2}*cos(170)\\d_{3}^{2} =952.5^{2} + 1270^{2} -2*952.5*1270*cos(170)\\d_{3}=2214.22mi$

The pilot is 2214.22 miles from her starting position

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2 years ago

Forces that are equal in strength and opposite indirection are

Otrada [13]

Hey there! My name is Christy and I'm gladly to help you out!

The three main forces that stop moving objects are friction, gravity and wind resistance. Equal forces acting inopposite directions are called balanced forces. Balanced forcesacting on an object will not change the object's motion. When you add equal forces in opposite direction, the netforce is zero.

Hope this helped!

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3 years ago

Read 2 more answers

The emission of x rays can be described as an inverse photoelectric effect.

timama [110]

Answer:

The potential difference through which an electron accelerates to produce x rays is $1.24\times 10^4\ volts$ .

Explanation:

It is given that,

Wavelength of the x -rays, $\lambda=0.1\ nm=0.1\times 10^{-9}\ m$

The energy of the x- rays is given by :

$E=\dfrac{hc}{\lambda}$

The energy of an electron in terms of potential difference is given by :

$E=eV$

So,

$\dfrac{hc}{\lambda}=eV$

V is the potential difference

e is the charge on electron

$V=\dfrac{hc}{e\lambda}$

$V=\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{1.6\times 10^{-19}\times 0.1\times 10^{-9}}$

V = 12431.25 volts

$V=1.24\times 10^4\ volts$

So, the potential difference through which an electron accelerates to produce x rays is $1.24\times 10^4\ volts$ . hence, this is the required solution.

4 0

2 years ago

2. A tiny pig is dropped from the top of a building and lands safely on a trampoline. The tiny pig will have

allsm [11]

Answer:

c. Kinetic energy

Explanation:

The two types of energy involved in this problem are:

- Potential energy: it is the energy possessed by an object due to its position. It is calculated as

$PE=mgh$

where

m is the mass of the object

g is the acceleration due to gravity

h is the height of the object relative to the ground

From the formula, we see that the higher the object is above the ground (higher h), the larger the potential energy of the object. In this problem, the pig is falling down, so the value of h is decreasing, therefore the potential energy is decreasing as well.

- Kinetic energy: it is the energy possessed by an object due to its motion. It is given by:

$KE=\frac{1}{2}mv^2$

where

m is the mass of the object

v is its speed

In this problem, as the pig falls down, it accelerates, so its speed increases: since the kinetic energy is proportional to the square of the speed, as the speed increases, its kinetic energy increases too. So, the correct answer is

c. Kinetic energy

4 0

3 years ago