Answer:
Average speed: 0.5 m/s. Average velocity: 0
Explanation:
Average speed is given by:
where
d is the total distance covered (the length, of one lap of the track, so d = 400 m)
t is the time taken to cover that distance (so, t = 800 s)
Substituting,
Instead, average velocity is defined as
where this time,
d is the displacement, which is the vector connecting the starting point to the final point of the motion
t is still the time taken (800 s)
However, in this case the walker starts and finishes his trip at the same point: therefore, the displacement is zero (d=0), and this means that the average velocity is zero as well.
1) B- adhesion
3) c- they increase friction
Answer:
The most accurate and precise method to measure the thickness of a coin would be by a micrometer screw guage.
Answer:
(in the same way that a faster runner overtakes a slower runner in an outside lane, the outer planet), it exhibits retrograde motion. True
Explanation:
The retrograde movement is the apparent movement of the planets in the opposite direction to the usual one. Retrograde motion is a projection effect because the Earth moves at a different speed than the other planets. The Greeks tried to explain it by proposing epicyclic movements. The apparent retrograde movement of Mars as seen from Earth is an illusion, produced by the combined effects of the orbital movement of the two planets. The retrograde rotation of Venus is real.