Answer:
Choice a. 1 kg, assuming that all other forces on the object (if any) are balanced.
Explanation:
By Newton's Second Law,
,
where
is the acceleration of the object in 
,
is the net force on the object in Newtons, and
is the mass of the object in kilograms.
As a result,
.
Assume that all other forces on this object are balanced. The net force on the object will be 
. The net force is constant. Acceleration should also be constant and the same as the average acceleration in the two seconds.
<h3>What is the
average acceleration of this object?</h3>
.
.
<h3>Apply Newton's Second Law to find the mass of the object.</h3>
.
Answer:
We can use 2 g H = v2^2 - v1^2 or
v2^2 = 2 g H + v1^2
Since 88 ft/sec = 60mph we have 30 mph = 44 ft/sec
The object will return with the same speed that it had initially so the object
starts out with a downward speed of 44 ft/sec
Then v2^2 = 2 * 32 ft/sec^2 * 160 ft + 44 (ft/sec)^2
v2^2 = (2 * 32 * 160 + 44^2) ft^2 / sec^2 = 12180 ft^2/sec^2
v2 = 110 ft/sec
The key principle is that crank length, just like frame size, should be proportional to the rider height and then modified to what fits the individual. There are 4 charts, two for the upright position and two for the aero position, depending upon how you race.
