Which of the following is an example of acceleration?
a) a twirling ballerina
b) a car on cruise control going 50 m/s east
c) mrs. crisp (my science teacher) sliding on the gym floor at +2.23 m/s
d) a remote control car traveling at a constant rate of 5 m/h

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.