Answer:
7 protons, 7 neutrons (READ EXPLANATION)
Explanation:
The atomic number represents how many protons are in an element. Generally speaking, elements have the same number of protons and neutrons. So, an element with the atomic number of 7 will have 7 protons and 7 neutrons.
However it is possible for an element to have a differing number of neutrons (an element will always have the same number of protons because that number is how the element is identified in the first place). Elements that have a number of neutrons that is not the same as the atomic number are called isotopes.
Potential energy = (mass) x (gravity) x (height) .
To raise the 20kg block 6 meters, you need to give it
(20 kg) x (9.8 m/s²) x (6 m) = 1,176 joules
of potential energy.
Your machine takes 2,000 joules of energy to give the block
the 1,176 joules that it takes.
Your machine is only (1176 / 2000) = 58.8% efficient .
The other 'missing' 824 joules of energy doesn't just disappear.
It heats the machine, and the air around it. The final result is
that when you use that machine to lift blocks, you have to use
even MORE energy, to blow cool air on the machine and prevent
it from overheating and breaking.
Control group
Explanation:
The control group usually serves as a reference for comparison during a scientific investigation.
What is a control group?
- The control group is an experimental group not being tested for.
- it does not receive any modification or design from the scientist.
- It is designed as a reference for the main experiment
- Often times, it is isolated from the main experiment and the independent variables cannot influence the outcomes of the experiment.
Learn more:
Controlled experiment brainly.com/question/1621519
#learnwithBrainly
Answer:
it helps a car slow down or pull to a stop I think
