Bungee Jumper Acceleration and Distance Problem

[tjb1]

Homework Statement

A bungie jumper falls for 1.3s before the bungee cord begins to stretch. Until the jumper has bounced back up to this level, the bungee causes the jumper to have an average acceleration upward of 4 m/s^2.
a. How fast is the jumper going when the bungee cord begins to stretch?
b.How far below the diving platform is the jumper at that moment?
c. How long after the bungee cord begins to stretch does the jumper reach the low point of the drop?
d. How far below the diving platform is the jumper at the instant the speed is zero?

Homework Equations

The Attempt at a Solution

I have gotten A which is 12.74 m/s^2, I am having trouble getting b though and I haven't even started c or d. This is my first Physics class ever and its in college so I am having a bit of trouble getting started here...

The teacher has posted the answers so we can check ourselves and the answer to B is 8.28m which I can get with 1/2*a*t but the appears to be the formula for velocity, and what exactly is the 12.74 m/s^2 and how do I get that to 12.74 m/s?

 

[Redbelly98]

Welcome to Physics Forums.

Homework Statement

A bungie jumper falls for 1.3s before the bungee cord begins to stretch. Until the jumper has bounced back up to this level, the bungee causes the jumper to have an average acceleration upward of 4 m/s^2.
a. How fast is the jumper going when the bungee cord begins to stretch?
b.How far below the diving platform is the jumper at that moment?
c. How long after the bungee cord begins to stretch does the jumper reach the low point of the drop?
d. How far below the diving platform is the jumper at the instant the speed is zero?

Homework Equations

The Attempt at a Solution

I have gotten A which is 12.74 m/s^2,

The question asks for a velocity or speed ("how fast...?"), but your answer has the units of acceleration. Can you show how you calculated this?

... I am having trouble getting b though and I haven't even started c or d. This is my first Physics class ever and its in college so I am having a bit of trouble getting started here...

The teacher has posted the answers so we can check ourselves and the answer to B is 8.28m which I can get with 1/2*a*t but the appears to be the formula for velocity,

I don't see you you can get 8.28m using 1/2*a*t.

Check your textbook or class lecture notes. There should be an equation for distance fallen, or traveled, in terms of time and acceleration -- perhaps using g.

... and what exactly is the 12.74 m/s^2 and how do I get that to 12.74 m/s?

If you show how you calculated the 12.74 m/s², I could probably help you figure out where the mistake is.

 

[tjb1]

I got 12.74 by 9.8m/s^2*1.3. And this textbook is horrible, it doesn't really have a formula, it just shows random examples that don't pertain to any of the problems.