Question
Please help, I used t=d/v but it says it's wrong, please show work, thank you!
Reading Passage Problem 2.60 From 1946 through 1958, Col. John Stapp headed the U.S. Air Force Aero Medical Laboratory's shudes of the human body's ability to tolerate high accelerations during plane crashes. Conventional wisdom at the time indicated that a plane's negative acceleration should not exceed 180 m/s (18 times gravitational acceleration, or 18 g) Stapp and his colleagues buit a 700-kg "Gee Whiz rocket sled, track, and stopping pistons to measure human tolerance to high acceleration Starting in June 1949, Stapp and other live subjects rode the sled. In one of Stapp's rides, the sled started at rest and 360 m later was traveling at speed 53 m/s when its braking system was applied, stopping the sled in 60 sm He had demonstrated that 18 g was not a limit for human deceleration Part A Find the time interval for Stapp and his sled to stop as their speed decreased from 53 m/s to zero Express your answer to two significant figures and include the appropriate units Give Up Incorrect; Try Again
Explanation / Answer
Initial velocity = u = 53 m/s
distance = s = 6.0 m
final velocity = v = 0 m/s
using v^2 = u^2 + 2as (negative sign indicates deceleration)
53^2 = 0 + 2*a*6
a = - 53^2/12 = -234 m/s^2
Taking g to be 10 m/s^2
a = -23.4g