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Physics

1 answer:

lara [203]3 years ago

4 0

The force is not pulling in the direction that the box is moving.
Only the force in the horizontal direction does work.
The force in the vertical direction doesn't do any work, because
   the box doesn't move through any vertical distance.

The horizontal force is 200(cos 45°) = 142 newtons

The vertical force is 200(sin 45°) = 142 newtons

If you pull the box 5 meters, then the amount of work done is

   (force) x (distance) = (142 N) x (5 m) = 710 joules.

Power = (work done) / (time to do the work)

   = (710 joules) / (5 seconds) = 142 watts .

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An object is moving at a constant speed along a straight line. Which of the following statements is not true? A. There must be a

Svetradugi [14.3K]

Answer:

False statement = There must be a non-zero net force acting on the object.

Explanation:

An object is moving at a constant speed along a straight line. If the speed is constant then its velocity must be constant. We know that the rate of change of velocity is called acceleration of the object i.e.

$a=\dfrac{dv}{dt}$

a = 0

⇒ The acceleration of the object is zero.

The product of force and acceleration gives the magnitude of force acting on the object i.e.

F = m a = 0

⇒ The net force acting on the object must be zero.

So, the option (a) is not true. This is because the force acting on the object is zero. First option contradicts the fact.

6 0

3 years ago

En un rio una Onda viaja con una velocidad de propagación de 50 m/s con una longitud de Onda de 40 metros. Hallar la frecuencia

sattari [20]

Answer:

Frequencia = 1.25 Hz

Explanation:

<u>Dados los siguientes datos;</u>

Velocidad = 50 m/s
Longitud de onda = 40 metros

Para encontrar la frecuencia de la onda;

Matemáticamente, la velocidad de una onda viene dada por la fórmula;

$Velocidad = Longitud \; de \; onda * Frequencia$

Haciendo de la frecuencia el tema de la fórmula, tenemos;

$Frequencia = \frac {Velocidad}{Longitud \; de \; onda}$

Sustituyendo en la fórmula, tenemos;

$Frequencia = \frac {50}{40}$

<em>Frequencia = 1.25 Hz</em>

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3 years ago

A 3kg object has an initial velocity (6i - 2j) m/s (a ) what is its kinetic energy at this time? (b) Find total work done on the

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Answer:

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