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Svetllana [295]
3 years ago
13

A train travels 55 kilometers in 2 hours, and then 52 kilometers in 5 hours. What is its average speed?

Physics
2 answers:
Dafna11 [192]3 years ago
6 0

Average speed = (total distance covered) / (time to cover the distance) .

Total distance covered = (55 km + 52 km) = 107 km

Time to cover the distance = (2 hrs + 5 hrs) = 7 hrs

Average speed = (107 km) / (7 hrs)

Average speed = 15.29 km/hour

bulgar [2K]3 years ago
4 0

The formula for working out speed is distance ÷ time.

55 km ÷ 2 hours = 27.5 km/h (average speed for first part of journey)

52km ÷ 5 hours = 10.4 km/h (average speed for second part of journey)

(27.5 + 10.4) ÷ 2 = 18.95 km/h (average speed throughout the journey)

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True or False. Recent findings lend strong support to the theory that a black hole lies at the center of the Milky Way and of ma
Genrish500 [490]

Answer:

True

Explanation:

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A radio telescope is an antenna that is capable to perceive the light in the radio part of the electromagnetic spectrum¹.

It is important to notice that in the picture what it can be seen is the effect that the black hole has in the nearby stars.

Key terms:

¹Electromagnetic spectrum: decomposition of light in its different wavelengths (from radio waves to gamma rays).

7 0
3 years ago
Your own car has a mass of 2000. Kg if your car produces a force of 5000 N how fast will it accelerate?
Marizza181 [45]
F = m*a
5000 = 2000 * x
5000/2000 = x
2.5 = x
2.5m/s^2 = a


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3 years ago
What is one way in which radioactive decay is used to benefit society?
snow_lady [41]
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7 0
3 years ago
Read 2 more answers
Two tiny particles having charges of +5.00 μC and +7.00 μC are placed along the x-axis. The +5.00-µC particle is at x = 0.00 cm,
Liula [17]

Answer:

The third charged particle must be placed at x = 0.458 m = 45.8 cm

Explanation:

To solve this problem we apply Coulomb's law:  

Two point charges (q₁, q₂) separated by a distance (d) exert a mutual force (F) whose magnitude is determined by the following formula:  

F = \frac{k*q_1*q_2}{d^2} Formula (1)  

F: Electric force in Newtons (N)

K : Coulomb constant in N*m²/C²

q₁, q₂: Charges in Coulombs (C)  

d: distance between the charges in meters (m)

Equivalence  

1μC= 10⁻⁶C

1m = 100 cm

Data

K = 8.99 * 10⁹ N*m²/C²

q₁ = +5.00 μC = +5.00 * 10⁻⁶ C

q₂= +7.00 μC = +7.00 * 10⁻⁶ C

d₁ = x (m)

d₂ = 1-x (m)

Problem development

Look at the attached graphic.

We assume a positive charge q₃ so F₁₃ and F₂₃ are repulsive forces and must be equal so that the net force is zero:

We use formula (1) to calculate the forces F₁₃ and F₂₃

F_{13} = \frac{k*q_1*q_3}{d_1^2}

F_{23} = \frac{k*q_2*q_3}{d_2^2}

F₁₃ = F₂₃

\frac{k*q_1*q_3}{d_1^2} = \frac{k*q_2*q_3}{d_2^2} We eliminate k and q₃ on both sides

\frac{q_1}{d_1^2}= \frac{q_2}{d_2^2}

\frac{q_1}{x^2}=\frac{q_2}{(1-x)^2}

\frac{5*10^{-6}}{x^2}=\frac{7*10^{-6}}{(1-x)^2} We eliminate 10⁻⁶ on both sides

(1-x)^2 = \frac{7}{5} x^2

1-2x+x^2=\frac{7}{5} x^2

5-10x+5x^2=7 x^2

2x^2+10x-5=0

We solve the quadratic equation:

x_1 = \frac{-b+\sqrt{b^2-4ac} }{2a} = \frac{-10+\sqrt{10^2-4*2*(-5)} }{2*2} = 0.458m

x_2 = \frac{-b-\sqrt{b^2-4ac} }{2a} = \frac{-10-\sqrt{10^2-4*2*(-5)} }{2*2} = -5.458m

In the option x₂, F₁₃ and F₂₃ will go in the same direction and will not be canceled, therefore we take x₁ as the correct option since at that point the forces are in  opposite way .

x = 0.458m = 45.8cm

8 0
3 years ago
Which statement is always false for athletes participating in team sports?
tatyana61 [14]
Which statement is always false for athletes participating in team sports?

Answer: Out of all the options shown above the one that best represents the statement that is alway false for athletes participating in team sports is answer choice C) Conflict resolution is a sign of poor sportsmanship. All the other choices are true when it comes to team sports.

I hope it helps, Regards.
3 0
3 years ago
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