Answer:
D
Explanation:
D) The overall work done by gravity is zero
This statement is correct .
If m be the mass of each of the children and h be the height of tower
work done by gravity on the boys in going up = - mgh
it is so because force applied by gravity = mg downwards and displacement
is upwards
work done will be negative = - mgh
Work done by gravity on boys when they come down = + mgh because both force and displacement are downwards .
Hence total work done = - mgh + mgh = 0.
The children will have same kinetic energy as the inclined surface is friction-less so no energy will be dissipated hence addition of energy to boys in both the cases will be same.
Answer:
humans and whales are both mammals
humans and whales can breathe air
Explanation:
Assuming we can turn on the lightbulb from any distance with a device. We can gradually increase the distance that separates us from lightbulb, in this way, if the speed of light is finite we can see a temporary delay between the moment we turn on the lightbulb and the moment in which we observe its light.
Answer: Option A
Explanation:
The potential energy decreases in the case when the charges are opposite and they attract each other.
In this case there is no external energy required in order to put the charges together.
This is so because the charges are opposite and they will attract each other. Yes, the only condition should be that the charges should be alike.
Example: a negative charge and a positive charge.
Solution:
The world record for the longest flight by a human cannonball is approximately 200 feet and therefore the human cannon catapult that Bobo would need is one that would be able to propel him with an initial velocity of more than 120 kilometer per hour (more than the speed of the current record holder) with the cannon directed at an angle 45 degrees above the horizonal
Learn more about the projectile motion here:
brainly.com/question/24240176
