When the object is at the top of the hill it has the most potential energy. If it is sitting still, it has no kinetic energy. As the object begins to roll down the hill, it loses potential energy, but gains kinetic energy. The potential energy of the position of the object at the top of the hill is getting converted into kinetic energy. Hope this helped. :)
<span>As long as both mirrors are set at 45% and the same size then you see the same as is reflected in the upper mirror </span>
<span>Put a lens in the middle of the tube </span>
<span>? </span>
<span>We use mirrors when we drive cars ect </span>
<span>Normally they are set across from a concealed entrance or one that is hard to see both ways like the inside of a hairpin bend. Sometimes only to help in one direction. </span>
<span>Sonar which is sound waves that are sent out at a set rate then reflected by objects. The longer the gap between the two the further away it is, They still use periscopes to target boats though. </span>
<span>The periscope can only reflect what is outside so if you could see it because there is enough light then Yes. If you could not see it because it is dark then No unless you get into Info-Red light or Image Intensifying systems as well </span>
Answer:
- 5436 J
Explanation:
mass of car, m = 120 kg
radius of loop, r = 12 m
velocity at the bottom (A) = Va = 25 m/s
Velocity at the top(B) = Vb = 8 m/s
Vertical distance from A to B = diameter of loop, h = 2 x 12 = 24 m
by use of Work energy theorem
Work done by all the forces = change in kinetic energy of the body
Work done by the force + Work done by the friction = Kinetic energy at B - kinetic energy at A
- m x g x h + Work done by friction = 0.5 x 120 x (Vb^2 - Va^2)
- 120 x 9.8 x 24 + Work done by friction = 60 x (64 - 625)
- 28224 + Work done by friction = - 33660
Work done by friction = -33660 + 28224 = - 5436 J
