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2 years ago

1.A car goes off a cliff horizontally at 49 m/s and falls for 5 seconds

1 answer:

3 0

#1). The horizontal speed doesn't change.
The vertical speed is accelerated by gravity.

a). Gravity increases the vertical speed by 9.8m/s every sec.
After 5 sec, the car is falling (5x9.8) = <em>49 m/s</em> vertically.

b). Horizontal: 49m/s ! Wow ! Almost 110 mph. No wonder he went off the cliff.
After 5 seconds, it's still <em>49 m/s</em>.

c). After 5 sec, the horizontal speed and vertical-down speed are both 49 m/s.
The combination results in a velocity that points 45 degrees down from horizontal,
and its magnitude is

square root of (49² + 49²) = 49 √2 = about <em>69.3 m/s</em> .

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Two teams of nine members each engage in a tug of war. Each of the first team’s members has an average mass of 68 kg and exerts

olga2289 [7]

Answer:

a) a = - 0.106 m/s^2 (←)

b) T = 12215.1064 N

Explanation:

F₁ = 9*1350 N = 12150 N (→)

F₂ = 9*1365 N = 12285 N (←)

∑Fx = M*a = (M₁ +M₂)*a (→)

F₁ - F₂ = (M₁ +M₂)*a

→ a = (F₁ - F₂) / (M₁ +M₂ ) = (12150-12285)N/(9*68+9*73)Kg

→ a = - 0.106 m/s^2 (←)

(b) What is the tension in the section of rope between the teams?

If we apply ∑Fx = M*a for the team 1

F₁ - T = - M₁*a ⇒ T = F₁ + M₁*a

⇒ T = 12150 N + (9 * 68 Kg)*(0.106 m/s^2)

⇒ T = 12215.1064 N

If we choose the team 2 we get

- F₂ + T = - M₂*a ⇒ T = F₂ - M₂*a

⇒ T = 12285 N - (9 * 73 Kg)*(0.106 m/s^2)

⇒ T = 12215.1064 N

4 0

3 years ago

How long have advances in astronomy been occurring? Only for the past few years

solniwko [45]

I'd have to say that the list of choices doesn't go far enough.

Advances in Astronomy have been occurring for at least the past two millennia (2000 years). Maybe longer.

3 0

3 years ago

A flat horizontal surface with an area of 518 cm^2 is inside a uniform electric field of 1.33 x 10^4 N/C. The angle between the

GarryVolchara [31]

Answer: 576.48 N*m^2/C

Explanation: In order to calculate the electric flux through the any surface we have to take into account the scalar product between the electric field vector and the normal vector to the surface.

So we have:

ФE= E*A= 1.33 * 10^4*0.0518* cos (33.2°)= 576.48 N*m^2/C

3 0

2 years ago

three girls were pushing the same car with a net force of 450 N [N48°E]. Two of the girls were pushing with forces of 310 N [N25

ElenaW [278]

The net force is the vector

∑ F = (450 N) (cos(42°) i + sin(42°) j)

and two of the forces provided by the girls are

F₁ = (310 N) (cos(115°) i + sin(115°) j)

F₂ = (250 N) (cos(285°) i + sin(285°) j)

Then the force provided by the third girl is the vector

F₃ = ∑ F - F₁ - F₂

F₃ = ((450 N) cos(42°) - (310 N) cos(115°) - (250 N) cos(285°)) i

… … … + ((450 N) sin(42°) - (310 N) sin(115°) - (250 N) sin(285°)) j

F₃ ≈ (400.722 N) i + (261.635 N) j

So, the third girl provided a force of magnitude

||F₃|| = √((400.722 N)² + (261.635 N)²) ≈ 478.572 N ≈ 480 N

pointing in a direction

arctan((261.635 N)/(400.722 N)) ≈ 33.1409° ≈ 33°

relative to East which refers to 0°; that is, 33° N of E or E33°N. Since the other forces are given relative to North or South, we can write this direction as N57°E.

So, the third girl pushed with force 480 N [N57°E].

5 0

2 years ago

Bats, which have a high-calorie diet of insects and face little danger from predators, sleep a lot. In contrast, cows, which hav

kherson [118]

The function of sleep theory supported by the illustration is sleep conserves and protects.

<h3>Positive impact of sleep</h3>

From the first sentence, bats sleep a lot because they face little danger from predators and as such, they have a high-calorie diet of insects.

<h3>Negative impact of sleep</h3>

From the second sentence, cows sleep less, because they face more danger from predators and as such, they have a low-calorie diet of insects.

We can conclude that sleep helps to keep animal safe. Therefore, the correct option will be, "Sleep conserves and protects".

Learn more about important of sleep here: brainly.com/question/10224591

8 0

1 year ago