Question

A certain freely falling object, released from rest, requires 1.85 s to travel the last 33.0 m before it hits the ground.

(a) Find the velocity of the object when it is 33.0 m above the ground. (Indicate the direction with the sign of your answer. Let the positive direction be upward.)


(b) Find the total distance the object travels during the fall.


I got 8.8 m/s for Part A but can't seem to get the correct answer for Part B (which I got 7.6 m).

Answer 1

From your answer to part A, you can calculate the total time the object was falling:
\[V_f = v_a - g * \Delta t \]
Substituting in the results:
\[V_f = -8.8 -10*1.85 = -27.3 (m/\sec)\]
Since the object is released from rest:
\[V_f = 0 -g*t_T\]
\[-27.3 = -10*t_T\]
\[t_T = 2.73\]
And now you can plug in the total falling time into y(t) eq. :
\[y(t) = -0.5*g*t_T^2\]
\[y(t_T) = -5*2.73^2 = 37.26(m)\]