How Tall Was the Initial Fall in a Physics Problem?

AI Thread Summary
To solve the problem of a freely falling object that takes 1.10 seconds to travel the last 20.0 meters before hitting the ground, the equations of motion for accelerated motion are essential. The second equation, d = Vi*t + 0.5*a*t^2, can be used to calculate the initial velocity (Vi) at the height of 20 meters. Once Vi is determined, the first equation, V = Vi + at, can be applied to find the height from which the object fell by determining when the velocity was zero. This approach effectively models the motion and provides the necessary calculations to find the initial height. Understanding these equations is crucial for solving similar physics problems.
ryno2107
Messages
3
Reaction score
0



A freely falling object requires 1.10 s to travel the last 20.0 m before it hits the ground. From what height above the ground did it fall? (Ans. in m.)

I am completely lost on modeling this problem. Please help me figure it out.
 
Physics news on Phys.org
The model is just accelerated motion so you have the usual
V = Vi + at and d = Vi*t + .5*a*t^2 to work with.
Looks like you don't have enough info to use the first one, but the second one can be used to get the Vi - the velocity at height 20 m.
That's a good start. Then you can use the first equation to found out when the velocity was zero.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggle to understand the concept of the question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Analyzing the Fall of a Chain: Problem 103 of 200 Puzzling Physics Problems
Replies
7
Views
2K
Linear Motion and Free Fall: Solving Projectile Motion Problems
Replies
4
Views
2K
Calculating Initial Velocity of a Thrown Object Using Free-fall Equations
Replies
23
Views
3K
How does halving the time affect the distance traveled by a falling object?
Replies
13
Views
2K
Oblique soccer shot calculation task
Replies
38
Views
4K
Free fall velocity and distance
Replies
34
Views
3K
Kinematics Question: Falling object
Replies
3
Views
2K
Calculating Safe Distance for Warning: Flower Pot Falling from 21.6m Height
Replies
8
Views
6K
A falling object travels one-fourth of its total distance in the last second of its fall....
Replies
12
Views
5K
Distance an object travels after sliding and falling from roof
Replies
8
Views
3K

Hot Threads

Recent Insights

Back
Top