To solve the exercise it is necessary to take into account the concepts of wavelength as a function of speed.
From the definition we know that the wavelength is described under the equation,

Where,
c = Speed of light (vacuum)
f = frequency
Our values are,


Replacing we have,



<em>Therefore the wavelength of this wave is
</em>
Answer:
-0.912 m/s
Explanation:
When the package is thrown out, momentum is conserved. The total momentum after is the same as the total momentum before, which is 0, since the boat was initially at rest.

where
are the mass of the child, the boat and the package, respectively.
are the velocity of the package and the boat after throwing.



Answer:
The power dissipated by the meter is 1188W
Explanation:
Here we have a circuit constituted with a power source and two resistors in series, we can calculate the power dissipated by the meter using the following formula:
We first need to fin the current going through the circuit:
because they are connected in series. So:
In physical terms, a force does work if it moves an object in the direction the force is pointing towards.
In your example, the force is pushing a tray up. But the force doesn't move the tray any further up. It remains at the same height.
The is no force done by this force.