the kinematics relations we were able to find the correct results:
- The distance traveled as a function of time
- The time for skull to open the paratroopers is 2.7 s
The kinematics allows finding the relationships between the position, the velocity and the acceleration of the bodies, in this case the boy is in free fall down the cliff, as he has a stopwatch in his hand he can mark the position every second that he falls, taken the downward direction as positive.
y = y₀ + v₀ t + ½ g t²
Where y and i are the current and initial height, vo the initial velocity, g the acceleration of gravity and t the time
As it is dropped, its initial velocity is zero and we place the zero of the reference system at the top of the cliff y₀ = 0
y = 0 + 0 + ½ g t²
y = ½ g t²
y = ½ 32.16 f²
y = 16.08 t²
Table 1 shows the distances for the first 5 seconds of the fall
t (s) y (ft)
0 0
1 16.08
2 64.32
3 144.72
4 257.28
5 402.0
In the attachment you can see a graph of distance versus time for this movement
b) We look for the time to obtain the speed of 60 mi / h
Let's reduce units of the speed to ft / s
v = 60 mi / h (5280 ft / 1 mi) (1h / 3600 s) = 88 ft / s
Let's use the kinematics relation
v = v₀ + g t
t =
t =
t = 2.7 s
Using the kinematics relations we were able to find the correct results
- The distance traveled as a function of time
- Tthe time for skull to open the paratroopers is 2.7 s
learn more about kinematics here:
