C. Ptolemy argued that earth was the center of the universe
Answer:
Explanation:
a) The second arm measures the minutes. The difference between 9:17:30 and 9:15:00 is 2 minutes 30 seconds. This means the second arm would have revolved 2.5 times.
The circumference = 2πr= 2π(13.5 cm) = 84.823 cm
Distance = 2.5 × 84.823 cm = 212 cm = 2.12 m
b) Displacement of an object is the shortest distance between the initial and final point. Since the second arm revolves 2 and half times, we use only the half times (a semicircle)
Displacement for semicircle = 2r = 2(13.5) = 27 cm
c) Average speed = distance / time
time = 2 minutes 30 seconds = 150 seconds
Average speed = 212 cm / 150 s = 1.41 cm/s
d) Average velocity = displacement / time = 27 cm / 150 s = 0.18 cm/s
e) number of revolutions = 100 m / circumference = 100 m / 0.848 m = 117.92
but 1 revolution = 1 minute
117.92 revolution = 117 minutes 55 seconds = 1 hour 57 minutes 55 seconds
Hence the time would be: 11:12:55
Answer:
W = 71J
Explanation:
Given force F = (5i+5j−1k)N
d = Δr
r1 = (−5,−3,−4)m
r2 = (2,5,0)m
Δr = r2 – r1 = (2-(-5), 5-(-3), 0-(-4))
Δr = (2+5, 5+3, 0+4) = (7i+ 8j +4k)m
W = F•d = (5i+5j−1k)•(7i+ 8j +4k)
W = 5×7 + 5×8 +-1×4 = 35 + 40 - 4
W = 71J
The last one. Opposites attract while similar ones repulse each other so all forces are pushing them apart
Mass of the are is 2100 kg
