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2 years ago

A piece of wood has a mass of 25g and a volume of 10cm3 What is its density?

Physics

1 answer:

Tasya [4]2 years ago

3 0

Answer:

<h3>The answer is 2.5 g/cm³</h3>

Explanation:

The density of a substance can be found by using the formula

$density = \frac{mass}{volume} \\$

From the question we have

$density = \frac{25}{10} = \frac{5}{2} \\$

We have the final answer as

Hope this helps you

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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) = $\frac{1}{f}$

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

2 years ago

The burner on a stove is 325° f. given that the burner emits electromagnetic radiation as a blackbody, what is the maximum wavel

lesantik [10]

To solve this, we use the Wien's Displacement Law as shown in the attached picture. First, convert the temperature to Kelvin.

C to F:
C = (F - 32)*5/9
C = (325 - 32)*5/9 = 162.78 °C

C to K:
K = C + 273
K = 162.78 + 273 = 435.78 K

λmax = 2898/435.78 = <em>6</em><em>.65 μm</em>

5 0

2 years ago

An object is originally moving at a constant velocity of 8 m/s in the -x direction. It moves at this constant velocity for 3 sec

aivan3 [116]

Answer:

244.64m

Explanation:

First, we find the distance traveled with constant velocity. It's simply multiplying velocity time the time that elapsed:

$x = V*t = -8\frac{m}{s} *3s = -24m$

After this, the ball will start traveling with a constant acceleration motion. Due to the fact that the acceleration is the opposite direction to the initial velocity, this motion will have 2 phases:

1. The velocity will start to decrease untill it reaches 0m/s.

2. Then, the velocity will start to increase at the rate of the acceleration.

The distance that the ball travels in the first phase can be found with the following expression:

$v^2 = v_0^2 + 2a*d$

Where v is the final velocity (0m/s), v_0 is the initial velocity (-8m/s) and a is the acceleration (+9m/s^2). We solve for d:

$d = \frac{v^2 - v_0^2}{2a} = \frac{(0m/s)^2 - (-8m/s)^2}{2*7m/s^2}= -4.57m$

Now, before finding the distance traveled in the second phase, we need to find the time that took for the velocity to reach 0:

$t_1 = \frac{v}{a} = \frac{8m/s}{7m/s^2} = 1.143 s$

Then, the time of the second phase will be:

$t_2 = 9s - t_1 = 9s - 1.143s = 7.857s$

Using this, we using the equations for constant acceleration motion in order to calculate the distance traveled in the second phase:

$x = \frac{1}{2}a*t^2 + v_0*t + x_0$

V_0, the initial velocity of the second phase, will be 0 as previously mentioned. X_0, the initial position, will be 0, for simplicity:

$x = \frac{1}{2}*7\frac{m}{s^2}*t^2 + 0m/s*t + 0m = 216.07m$

So, the total distance covered by this object in meters will be the sum of all the distances we found:

$x_total = 24m + 4.57m + 216.07m = 244.64m$

8 0

2 years ago

What is the speed of a commercial jet which travels form New York to Los Angeles (4800) in 6 hours

Colt1911 [192]

Answer:

$Speed = 800km}/hr$

Explanation:

Given

$Distance = 4800km$

$Time = 6hr$

Required

Determine the speed of the jet

The speed is calculated as:

$Speed = \frac{Distance}{Time}$

Substitute 4800 km for Distance and 6hr for Time

$Speed = \frac{4800km}{6hr}$

$Speed = 800km}/hr$

<em>Hence, the speed of the commercial jet is 800km/hr</em>

8 0

2 years ago

Jaden has a mass of 45 kilograms on Earth. Jupiter has more gravity than the Earth. On Jupiter, Jaden's mass will be O more than

Dovator [93]

Answer:

m = 45 kg

Explanation:

Given that,

Mass of Jadan, m = 45 kg on Earth

Jupiter has more gravity than the Earth.

Mass of an object is the amount of matter contained inside an object. We need to tell about the mass of Jaden on Jupiter. The mass of the object remains same everywhere.It does not change in any of the location.

Hence, Jaden's mass will be 45 kg on Jupiter.

7 0

1 year ago