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3 years ago

What is the speed of a train if it covers 69 km in 45 minutes.

Physics

1 answer:

never [62]3 years ago

5 0

Answer:

1.4km/h

Explanation:

distance/time = speed

69/45=1.4km/h

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Write an expression for a harmonic wave with an amplitude of 0.19 m, a wavelength of 2.6 m, and a period of 1.2 s. The wave is t

zlopas [31]

Answer:

$y = 0.19 sin(5.23 t - 2.42x + \frac{\pi}{2})$

Explanation:

As we know that the wave equation is given as

$y = A sin(\omega t - k x + \phi_0)$

now we have

$A = 0.19 m$

$\lambda = 2.6 m$

so we have

$k = \frac{2\pi}{\lambda}$

$k = \frac{2\pi}{2.6}$

$k = 2.42 per m$

also we have

$T = 1.2 s$

so we have

$\omega = \frac{2\pi}{T}$

$\omega = \frac{2\pi}{1.2}$

$\omega = 5.23 rad/s$

now we know that at t = 0 and x = 0 wave is at y = 0.19 m

so we have

$\phi_0 = \frac{\pi}{2}$

so we have

$y = 0.19 sin(5.23 t - 2.42x + \frac{\pi}{2})$

6 0

3 years ago

What are sun spots??????????

babymother [125]

Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Sunspots usually appear in pairs of opposite magnetic polarity.

4 0

3 years ago

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Accurate data _____. A)is free from error B)proves a hypothesis C)disproves a hypothesis D)is always precise

maxonik [38]

The correct choice for this problem is (a)

8 0

3 years ago

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The rotational kinetic energy term is often called the kinetic energy in the center of mass, while the translational kinetic ene

Nataliya [291]

Question in proper order

The rotational kinetic energy term is often called the kinetic energy in the center of mass, while the translational kinetic energy term is called the kinetic energy of the center of mass.

You found that the total kinetic energy is the sum of the kinetic energy in the center of mass plus the kinetic energy of the center of mass. A similar decomposition exists for angular and linear momentum. There are also related decompositions that work for systems of masses, not just rigid bodies like a dumbbell.

It is important to understand the applicability of the formula

$Ktot=Kr+Kt$

Which of the following conditions are necessary for the formula to be valid?

a. The velocity vector $v$ must be perpendicular to the axis of rotation

b.The velocity vector $v$ must be perpendicular or parallel to the axis of rotation

c. The moment of inertial must be taken about an axis through the center of mass

Answer:

Option c

Explanation:

$K_{total} = K_{rotational}+K_{translational}$

The first two conditions are untrue, this is because, you can have rotation in any direction and translation in any direction of any collection of masses. Rotational and translational velocities of masses do not depend on each other

The last statement is true because by definition, the moment of inertia, which is a measure of reluctance, is usually taken about a reference point which is the center of mass

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3 years ago

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Can someone help me

SOVA2 [1]

Answer:

Explanation:before the phase change the substance is a particle.

8 0

3 years ago