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3 years ago

Cuestionario:

Physics

1 answer:

Sati [7]3 years ago

3 0

Explanation:

1.El objetivo principal de realizar la llamada entrada en calor o calentamiento, es preparar el cuerpo para la actividad física o deportiva. Numerosas lesiones y ciertos problemas cardíacos como algunas arritmias, están asociados a la ejercitación violenta sin mediar un adecuado calentamiento.

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A budding magician holds a 2.24-mW laser pointer, wondering whether he could use it to keep an object floating in the air with t

Sonbull [250]

Answer:

W = 1.49 10⁻¹¹ kg

Explanation:

For this problem, let's use Newton's equation of equilibrium

F - W = 0

F = W (1)

Strength can be found from the definition of pressure

P = F / A

F = P A

The radiation pressure for a reflective surface is

P = 2 I / c)

We substitute in equation 1

2 I / c A = W

The intensity is defined by the ratio of the power between the area

I = P / A

P = I A

We substitute

2 P / c = W

W = 2 2.24 10-3 / 3 108

W = 1.49 10⁻¹¹ kg

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4 years ago

Which chemical reaction releases the most energy?

IceJOKER [234]

A.nuclear chain reaction

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4 years ago

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12.0-kg block is pushed across a rough horizontal surface by a force that is angled 30.0◦below thehorizontal. The magnitude of t

drek231 [11]

Answer: Fr = 26.53 N

Explanation: The constant force exerted on the block by the surface is the frictional force.

This frictional force is as a result of interaction between the body and the surface.

According to newton's second law of motion,

F - Fr = ma

F=applied force

Fr = magnitude of frictional force

m = mass of object = 12kg

a = acceleration of object = 3.2m/s²

The applied force (F= 75 N) is inclined at an angle of 30° to the horizontal thus making it have 2 components of forces given below

Fx = 75 * cos 30 = 64.95 N (horizontal component)

Fy = 75 * sin 30 = 37.5 N ( vertical motion)

The body moves across the surface, hence the horizontal component of force is responsible for motion.

F = 64.95 N

By substituting the parameters, we have that

64.96 - Fr = 12 * 3.2

64.96 - Fr = 38.4

Fr = 64.96 - 38.4

Fr = 26.53 N

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3 years ago

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If velocity is 0.2m/s, what is the kinetic energy?

Natalija [7]

$\huge\boxed{♧ \: \mathfrak{ \underline{Answer} \: ♧}}$

we know,

$\boxed{kinetic \: \: energy = \frac{1}{2} m {v}^{2} }$

So,

$\longmapsto \dfrac{1}{2} \times 10 \times 0.2 \times 0.2$

$\longmapsto0.2 \: joules$

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3 years ago

Lions can run at speeds up to approximately 80.0 km / h. A hungry 109 kg lion running northward at top speed attacks and holds o

sukhopar [10]

Answer:

17.34 m/s

Explanation:

Given:

Mass of lion (m₁) = 109 kg

Initial speed of lion (v₁) = 80.0 km/h (Northward direction)

Mass of gazelle (m₂) = 39.0 kg

Initial speed of gazelle (v₂) = 78.5 km/h (Eastward direction)

Final velocity of both lion and gazelle is, $v_f=?$

First, let us convert the speeds from km/h to m/s using the conversion factor.

We know that, 1 km/h = 5/18 m/s

Therefore,

$v_1= 80.0\ km/h=80\times \frac{5}{18}=22.22\ m/s\\\\v_2=78.5\ km/h=78.5\times \frac{5}{18}=21.81\ m/s$

Now, the concept of conservation of total momentum is used here as this is a case of perfectly inelastic collision. In inelastic collision, the masses move together with same velocity after collision.

Here, as the lion and gazelle are moving in directions at right angles to each other, the vector sum of their momentums will give the net initial momentum of the system.

So, initial momentum is given as:

$P_i=\sqrt{P_1^2+P_2^2}\\\\Where,\\\\P_1\to initial\ momentum\ of\ lion\\P_2\to initial\ momentum\ of\ gazelle$