Answer:
The force is 
Explanation:
From the question we are told that
The mechanical advantage is
The load is
The height is 
Generally mechanical advantage is mathematically represented as

Here E is the force that must be applied to move the piano
=> 
=> 
=> 
Answer:
They oscillates perpendicularly to one another, the oscillation of one field generates the other field.
Explanation:
In a light wave, an oscillating electric field of a light wave produces a magnetic field, and the magnetic field also oscillates to produce an electric field. The magnetic field and the electric field of a light wave both oscillates perpendicularly to one another. The resultant energy and direction of the wave generated as a result of these oscillating fields is propagated perpendicularly to both fields.
Place the boxes 10cm apart, if they are closer that concentrates the mass of the boxes more
The molecules of a solid vibrate faster so that they start spreading out to become a liquid. This energy makes them vibrate faster so the bonds between molecules can't interact all that well anymore creating more distance. The stronger the bonds between the molecules the higher the energy (temperature) has to be to get them away from each other. Hope I didn't confuse you too much!
<u>Mass</u>
- Mass is measured in kilograms.
- Mass does not change when gravity changes.
- Mass is the amount of matter in something.
<u>Weight</u>
- Before I answer, we have to know weight formula. Weight = mass × acceleration due to gravity.
- Therefore, weight is measured in Newtons.
- Weight changes when gravity changes. This is because weight is dependent on acceleration due to gravity.
- Weight is a gravitational force.
Hope you could understand.
If you have any query, feel free to ask.