To solve this problem, we can use the kinematic equation:
distance (d) = initial velocity (u) * time (t) + (1/2) * acceleration (a) * time (t)^2
We are given specific distances for the first 6 seconds and the last 3 seconds, which can help us find the acceleration (a). Here's how we do it step by step:
Step 1: Calculate the acceleration (a):
Using the distance formula, d = ut + (1/2)at^2, for the first 6 seconds:
246 = u * 6 + (1/2) * a * 6^2
246 = 6u + 18a (equation 1)
Using the distance formula, d = ut + (1/2)at^2, for the last 3 seconds:
69 = u * 3 + (1/2) * a * 3^2
69 = 3u + 4.5a (equation 2)
Step 2: Solve the simultaneous equations:
From equation 1, we can express 6u as 246 - 18a and substitute it into equation 2:
69 = (246 - 18a) + 4.5a
69 = 246 - 18a + 4.5a
69 - 246 = -13.5a
-177 = -13.5a
a = (-177) / (-13.5) = 13.11 m/s^2 (approx.)
Step 3: Find the initial velocity (u):
Substitute the value of acceleration (a) into equation 1:
246 = 6u + 18 * 13.11
246 = 6u + 235.98
6u = 246 - 235.98
6u = 10.02
u = 10.02 / 6 = 1.67 m/s (approx.)
Step 4: Calculate the total distance traveled in 12 seconds:
Using the distance formula for the entire 12 seconds:
d = ut + (1/2)at^2
d = 1.67 * 12 + (1/2) * 13.11 * 12^2
d = 20.04 + 93.852
d = 113.892 m (approx.)
Therefore, the body travels approximately 113.892 meters in 12 seconds, and the initial velocity is approximately 1.67 m/s.