Answer:
all of those are pisitions
Explanation:
The correct answer is B.
In a velocity vs time graph, a line going up means an increase in velocity, or speed, which correlates to positive acceleration. Negative acceleration means slowing down.
A machine can never be 100% efficient because some work is always lost
due to the lack of materials or equipment that would convert work by 100%. It follows
the second law of entropy. The ideal engine is known as Carnot’s engine having
a 100% efficiency. So far, no engine has ever gotten to 100%.
Answer:
0.66c
Explanation:
Use length contraction equation:
L = L₀ √(1 − (v²/c²))
where L is the contracted length,
L₀ is the length at 0 velocity,
v is the velocity,
and c is the speed of light.
900 = 1200 √(1 − (v²/c²))
3/4 = √(1 − (v²/c²))
9/16 = 1 − (v²/c²)
v²/c² = 7/16
v = ¼√7 c
v ≈ 0.66 c
