- #1
Pushoam
- 962
- 51
Homework Statement
Homework Equations
The Attempt at a Solution
A) W.r.t. Earth's frame,
After 2s , velocity of bolt = at = 1.2*2 = 2.4 m/s
distance traveled = (1/2) 1.2*22 = 2.4 m
Let's say that the bolt reaches the floor at time t.
Using s = ut + (1/2)at2
2.4 = 2.4t +(1/2)(-9.8) t2
Solving this equation doesn't give proper answer.
After leaving the car, the bolt goes up till its speed becomes 0 m/s. Let's say that this process takes the time t1 and by this time the bolt travels a distance s1.
0 = 2.4 - 9.8t 1
t1 = 2.4/9.8 = 0.245
s1 = 2.4* 0.245 + (1/2)(-9.8)0.2452 =0.294 m
After the speed of the bolt becomes 0, the bolt starts falling down.
Let's say that the bolt takes time t2 to reach the floor from now.
So,
s + s1 = (1/2)9.8 t2
Solving this gives t2 = 0.741s
What is meant by free fall time ?
t2 = 0.741 s or t2 + t1 = 0.986 s ?
b) W.r.t. elevator,Taking t2 as the free fall,
The displacement is
d = s + s1 +[ {1.2*(2 + t1 )} t2 + (1/2) 1.2 * t22 = 5.019 m where the bold part is distance traveled by the car in time t2
The distance is D = d+ s1 = 5.019+0.294= 5.313 m,