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3 years ago

Instructions:Select all the correct answers.

Physics

2 answers:

malfutka [58]3 years ago

4 0

The correct answer is 1 and 4.

Burning of fossil fuels releases harmful gases to the atmosphere which leads to climate change. Burning of hydrogen gas releases water which has no negative effect on climate.

Burning of both fossil fuels and hydrogen takes place inside expensive fuel cells.

Fossil fuels are widely available and easy to locate whereas hydrogen is available in the combined form with other elements. Hydrogen are not found in pure form on earth.

Fossil fuels are non-renewable source of energy which means they cannot be replaced in short time.

pogonyaev3 years ago

4 0

1 & 4 would be what you looking for

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A fighter bomber is making a bombing run flying horizontally at 500 knots (256m/s) at an altitude of 100.0m.

Jobisdone [24]

Answer:

(a) t = 4.52 sec

(b) X = 1,156.49 m

Explanation:

Horizontal Launching

If an object is launched horizontally, its initial speed is zero in the y-coordinate and the horizontal component of the velocity $v_o$ remains the same in time. The distance x is computed as .

$\displaystyle x=v_o.t$

(a)

The vertical component of the velocity $v_y$ starts from zero and gradually starts to increase due to the acceleration of gravity as follows

$v_y=gt$

This means the vertical height is computed by

$\displaystyle h=h_o-\frac{gt^2}{2}$

Where $h_o$ is the initial height. Our fighter bomber is 100 m high, so we can compute the time the bomb needs to reach the ground by solving the above equation for t knowing h=0

$\displaystyle t=\sqrt{\frac{2h_o}{g}}$

$\displaystyle t=\sqrt{\frac{2(100)}{9.8}}=4.52\ sec$

(b)

We now compute the horizontal distance knowing $v_o=256\ m/s$

$\displaystyle x=(256).(4.52)$

$X=1,156.49\ m$

4 0

3 years ago

What mechanical layer lies below the lithosphere

joja [24]

The asthenosphere is under the lithosphere.

3 0

3 years ago

Read 2 more answers

Why is a neutral object attracted to a charged object?

mixas84 [53]

Because electricity attracts like people

7 0

3 years ago

Consider a uniform horizontal wooden board that acts as a pedestrian bridge. The bridge has a mass of 300 kg and a length of 10

gayaneshka [121]

Answer:

F = 2123.33N

Explanation:

In order to calculate the torque applied by the left support, you take into account that the system is at equilibrium. Then, the resultant of the implied torques are zero.

$\Sigma \tau=0$

Next, you calculate the resultant of the torques around the right support, by taking into account that the torques are generated by the center of mass of the wooden, the person and the left support. Furthermore, you take into account that torques in a clockwise direction are negative and in counterclockwise are positive.

Then, you obtain the following formula:

$-\tau_l+\tau_p+\tau_{cm}=0$ (1)

τl: torque produced by the left support

τp: torque produced by the person

τcm: torque produced by the center of mass of the wooden

The torque is given by:

$\tau=Fd$ (2)

F: force applied

d: distance to the pivot of the torque, in this case, distance to the right support.

You replace the equation (2) into the equation (1) and take into account that the force applied by the person and the center of mass of the wood are the their weight:

$-Fd_1+W_pd_2+W_{cm}d_3=0\\\\d_1=6.0m\\\\d_2=2.0m\\\\d_3=3.0m\\\\W_p=(200kg)(9.8m/s^2)=1960N\\\\W_{cm}=(300kg)(9.8m/s^2)=2940N$

Where d1, d2 and d3 are distance to the right support.

You solve the equation for F and replace the values of the other parameters:

$F=\frac{W_pd_2+W_d_3}{d_1}=\frac{(1960N)(2.0m)+(2940N)(3.0m)}{6.0m}\\\\F=2123.33N$

The force applied by the left support is 2123.33 N

8 0

3 years ago

A microwave oven operates at 2.00 ghz . what is the wavelength of the radiation produced by this appliance? express the waveleng

yan [13]

Since frequency and wavelength have inverse relationship. It can be expressed by the equation: Î˝.Î» = c Where, v = frequency of the electromagnetic wave. Î» = it's wavelength c = the speed of light in a vacuum. v = 2.00 Ghz x 10^9 Hz / 1 Ghz = 2.00 x 10^9 Hz that means that in one second it covers 2.00 x 10^9 cycles. Î» = 3.10^8 m/s / 2.00 x 10^9 /s = 1.25E-10 nanometers

7 0

3 years ago