You are here:

Calculus/Solving acceleration problems

Advertisement

Expert: - 6/9/2008


Question
I dont know if this is your field but if you could help me at all Id really appreciate it.

A object is projected upwards from a 20m tower. If it takes 4.5 seconds for the object to hit the ground, what is the initial velocity of the object?

I cant figure out the initial velocity becuase I only have acceleration (gravity) and the total time.

Can you please help?

Answer
Maybe I should put in there I know some physics and some chemistry as well (since I do).

The basic equation for height h = d0 + v0(t) - 0.5a*t^2 where d0 is the original height, v0 is the original speed, and a is the acceleration due to gravity.

Note that all of the values are in meters.
Plugging in the values given, we know that d0 = 20, v0 is unknown,
a = 9.8m/s^2, and the final height is 0.

Put 4.5 in for t into the h equation and v0 can be found by solving the equation -4.9*(4.5)^2 + 4.5v0 + 20 = 0.

Calculus

All Answers

Answers by Expert:

Ask Experts

Volunteer

Scotto

Expertise

Any kind of calculus question you want. I also have answered some questions in Physics (mass, momentum, falling bodies), Chemistry (charge, reactions, symbols, molecules), and Biology.

Experience

Experience in the area: I have tutored students in all areas of mathematics for over 25 years. Education/Credentials: BSand MS in Mathematics from Oregon State University, where I completed sophomore course in Physics and Chemistry. I received both degrees with high honors. Awards and Honors: I have passed Actuarial tests 100, 110, and 135.

Publications
Maybe not a publication, but I have respond to well oveer 7,500 questions on the PC. Well over 2,000 of them have been in calculus.

Education/Credentials
I aquired well over 40 hours of upper division courses. This was well over the number that were required. I graduated with honors in both my BS and MS degree from Oregon State University. I was allowed to jump into a few junior level courses my sophomore year.

Awards and Honors
I have been nominated as the expert of the month several times. All of my scores right now are at least a 9.8 average (out of 10).

Past/Present Clients
My past clients have been students at OSU, students at the college in South Seattle, referals from a company, friends and aquantenances, people from my church, and people like you from all over the world.

©2012 About.com, a part of The New York Times Company. All rights reserved.