a) PE=mgh=0.2*9.8*1.2=2.352 J
b) KE=PE=2.352 J
c) 
m/s
If it goes 1250km every hour, times 4.2 hours
1250*4.2
5250 km
Answer:
The pressure of the air molecules inside the pen cap increases and the volume occupied by the air decreases such that the combined volume occupied by the pen cap and the air volume reduces while the combined mass of the pen cap and the air molecules remain the same
Given that density = The mass/Volume, we have that the density varies inversely as the volume, and as the volume reduces, the density increases
Upon squeezing, therefore, as the new combined density of the pen cap and the air molecules rises to more than the density of the water in the bottle, then, the pen cap air molecule is relatively more denser than the water, which will result in the pen cap sinking to the bottom of the bottle
Explanation:
In this experiment, the independent variable is the surface, the dependant variable is the distance one end of the surface must be lifted to see movement of the object, and the control variable is the object. Since the surface height at one end is changed and the object is kept the same, the only conclusion that can be made is whether the surface has an effect on the force of friction. Of course, basic physics tells you that it does, therefore A is correct.
Answer:
check the screen shot please
