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3 years ago

7

The energy expenditure value of traveling by car is 3.6 MJ/passenger-kilometer. For one person making a trip of 1000 km, if a ga

llon of gasoline contains 120 MJ, approximately how many gallons of gasoline would be required

1 answer:

mash [69]3 years ago

8 0

Answer:

30[gal] would be requiered.

Explanation:

The consumption ratio is given by the following expression:

$\frac{3.6[MJ]}{[1pass-km]}$

To find the amount of energy needed we must multiply the ratio by the number of passengers, in this way the unit passenger-kilometer is removed from the denominator.

$\frac{3.6[MJ]}{[1 pass-km]}*1[pass-1000km]\\\\ = 3600[MJ]$

1 gal = 120 [MJ]

x = 3600[MJ]

x = 30 [gal]

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A stone is thrown upward from the top of a building at an angle of 30° to the horizontal and with an initial speed of 20 m/s. Th

Hitman42 [59]

Answer:

Explanation:

Given

inclination $\theta =30^{\circ}$

initial speed $u=20\ m/s$

Point of release is 45 m above the ground

Considering stone to be a projectile, so time taken by projectile for its zero vertical displacement is

$t_1=\frac{2u\sin \theta }{g}$

$t_1=\frac{2\times 20\times \sin 30}{10}$

$t_1=2\ s$

Now after completing zero vertical displacement , stone needs to travel another 45 m in downward direction with initial speed u=20\sin 30

$h=u_yt+\frac{1}{2}a_yt^2$

where, $h=height$

$u_y=vertical velocity$

$a_y=vertical acceleration$

$t_0=time$

$45=20\sin 30+\frac{1}{2}(9.8)(t_0)^2$

$t_0^2=\frac{70}{9.8}$

$t_0=2.64\ s$

thus total time time required is $t=t_0+t_1=2.64+2=4.64\ s$

vertical velocity just before hitting

$v_y=\sqrt{u_y^2+2\times a_y\times s}$

$v_y=\sqrt{10^2+2\times 10\times 45}$

$v_y=\sqrt{1000}=31.622\ m/s$

Horizontal velocity $v_x=u\cos 30=17.32\ m/s$

Net velocity Just before hitting $=\sqrt{v_x^2+v_y^2}$

$=\sqrt{(17.32)^2+(31.62)^2}$

$=\sqrt{1299.82}=36.05\ m/s$

7 0

3 years ago

Would anyone be kind enough to help me? :)

Travka [436]

Answer:

The racetrack is 996.7 meters long

Explanation:

Convert 251km/h to km/s (kilometers per second)

3600 seconds in an hour, so:

251/3600 = 0.0697km/s

Convert km/s to m/s (meters per second)

1000 meters in a kilometer, so:

0.0697*1000 = 69.7m/s

Find length of racetrack:

69.7m/s*14.3s = 996.7m

If the racer travels 69.7 meters in one second and it takes 14.3 seconds to complete a lap, the racetrack is 996.7 meters long.

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2 years ago

Technician A says that the cooling system should be tested for leaks using a pressure-operated pressure pump. Technician B says

mart [117]

Answer:

The correct option is;

Technician A only

Explanation:

Leaks in the cooling system parts such as the radiator cap can be tested with a pressure operated hand pump by attaching the pump cap to the pump with an adaptor and apply pressure enough for there to be a release of pressure at the cap.

The pressure added to the system should be maintained for up to two minutes. If the pressure drops quicker, then there is likely to be leaks in the system

The freezing and boiling point of the coolant is measured with an antifreeze tester which carries the appropriate apparatus to measure the coolants freezing and boiling points.

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2 years ago

You have DNA samples from five different suspects. You know that all humans have very similar DNA. What feature of DNA allows yo

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Answer:

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Confirmed by my Forensics test today.

Explanation:

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2 years ago

A new ride being built at an amusement park includes a vertical drop of 126.5 meters. Starting from rest, the ride vertically dr

yan [13]

Answer:

49.79 m/s

Explanation:

Given:

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Vertical drop or the displacement of the roller coaster is, $y=-126.5\ m$

The displacement is negative as the motion is in downward direction.

Now, as the motion is in vertical direction only, the acceleration of the roller coaster will be due to gravity acting in the downward direction.

So, the acceleration of the roller coaster is, $a=g=-9.8\ m/s^2$

Now, using the following equation of motion:

$v^2=u^2+2ay$

Where, 'v' is the velocity of the roller coaster at the bottom.

Plug in all the given values and solve for 'v'. This gives,

$v^2=0^2+2(-9.8)(-126.5)\\\\v^2=2479.4\\\\v=\sqrt{2479.4}\\\\v=49.79\ m/s$

Therefore, the speed of the roller coaster at the bottom of the drop is 49.79 m/s.

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3 years ago