Answer:
work done = ( force × displacement)
(a)The force acting on the block is it's self weight and displacement is equal to height of the tower.
work done by gravity = (250 × 10) = 2500 joule
(b) The work done by gravity 2500 joule is transferred to the object in the form of it's kinetic energy.
First, we have a change in the velocity from 85 to 164 m/s in 10 sec.
Then, we calculate the <u>acceleration </u>as:

Hence we need to calculate the velocity of the space vehicle at t = 2 sec using the first equation of motion:

Then, using the second equation of motion to calculate the distance:


Wavelength is defined as distance between two troughs or two crests !!
so in this wavelength is 4 metres !!
Answer:
Block A will have a final charge of 3.5nC.
Explanation:
This is because at the point of contact with Block B, which is electrically positive, the electrons in Block A will be attracted to the excess 'unpaired' protons in block B. Hence, the electrons will flow into Block B causing unpaired protons to remain in Block A.
This process is called Charging by Conduction.
This charging process will continue until the charges are evenly distributed between both objects.
In case you're wondering, "<em>how's all this possible within a few seconds</em>?", remember that electrons travel very fast and so, this process is a rather rapid one.