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lara [203]
3 years ago
14

12. The diameter of a circle is 2.42m. Calculate itsarea in proper significant figure​

Physics
1 answer:
Sever21 [200]3 years ago
7 0

Answer:

A = 4.6 [m²]

Explanation:

The area of a circle can be calculated by means of the following equation.

A=\frac{\pi }{4} *D^{2}

where:

A = area [m²]

D = diameter = 2.42 [m]

Now replacing:

A=\frac{\pi }{4} *(2.42)^{2} \\A = 4.6 [m^{2} ]

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A shell is fired at an angle of 35° above the horizontal at a velocity of 40 m/s. (a) What is it's speed at the highest point of
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Answer:

Part a)

v_f = v_x = 32.77 m/s

Part b)

T = 4.68 s

Explanation:

Part a)

Shell is fired at speed of 40 m/s at angle of 35 degree

so here we have

v_x = 40 cos35 = 32.77 m/s

v_y = 40 sin35 = 22.94 m/s

since gravity act opposite to vertical speed of the shell so at the highest point of its trajectory the vertical component of the speed will become zero

so at the highest point the speed is given

v_f = 32.77 m/s

Part b)

After completing the motion we know that the displacement of the object will be zero in Y direction

so we have

\Delta y = 0

0 = v_y t - \frac{1}{2}gt^2

T = \frac{2v_y}{g}

T = \frac{2(22.94)}{9.81} = 4.68 s

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3 years ago
All electromagnetic waves
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Electromagnetic Waves:

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3 0
3 years ago
Velocity of B rays ?<br>​
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Answer:

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6 0
3 years ago
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Radar uses radio waves of a wavelength of 2.9 m . The time interval for one radiation pulse is 100 times larger than the time of
Mandarinka [93]

Answer:

145 m

Explanation:

Given:

Wavelength (λ) = 2.9 m  

we know,

c = f × λ  

where,

c = speed of light ; 3.0 x 10⁸ m/s

f = frequency  

thus,

f=\frac{c}{\lambda}

substituting the values in the equation we get,

f=\frac{3.0\times 10^8 m/s}{2.9m}

f = 1.03 x 10⁸Hz  

Now,

The time period (T) = \frac{1}{f}

or

T =  \frac{1}{1.03\times 10^8}  = 9.6 x 10⁻⁹ seconds  

thus,

the time interval of one pulse = 100T = 9.6 x 10⁻⁷ s  

Time between pulses = (100T×10) = 9.6 x 10⁻⁶ s  

Now,

For radar to detect the object the pulse must hit the object and come back to the detector.

Hence, the shortest distance will be half the distance travelled by the pulse back and forth.

Distance = speed × time = 3 x 10^8 m/s × 9.6 x 10⁻⁷ s) = 290 m {Back and forth}  

Thus, the minimum distance to target = \frac{290}{2} = 145 m

6 0
3 years ago
Acid rain contributes to soil erosion. Acid rain can be caused by 
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It can be caused by chemical reactions like sulfur dioxide and nitrogen oxides. These can rise very high in the atmosphere. They can mix in with oxygen and rain and thats where you get your acid rain from

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6 0
4 years ago
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