Answer:
A reference frame is that frame to which the qualities of an object are related:
For instance - an object may described by - mass, speed, acceleration, size, etc,
It is important to remember that Newton's Laws of motion do not hold in accelerated reference frames -
Einstein's laws of special relativity are only true in frames that move with contant speed to one another
Answer:
Your pinball machine was built using two kinds of simple machines: a lever and an inclined plane. The lever shot the marble to the top of the box with lots of force. The inclined planes made the marble wind its way down to the bottom.
Gradient of the line is m =-2/5
The answer to this questions would be nuclear engineer. The overall career of engineering would require physics as engineers need to know how the overall mechanics of nature affect the way their structure is built.
Hope this helped :D