Question

Dr. John Paul Stapp was a U.S. Air Force officer who studied the effects of extreme deceleration on the human body. On December 10, 1954, Stapp rode a rocket sled, accelerating from rest to a top speed of 282 m/s (1015 km/h) in 5.00 s, and was brought jarringly back to rest in only 1.40 s. Calculate his:

a. acceleration in his direction of motion
b. acceleration opposite to his direction of motion.

Answer 1

Answer: $56.4\ m/s^2, 201.42\ m/s^2$

Explanation:

Given

Rocket attain a velocity of $v=282\ m/s$ in a time period of $t=5\ s$

It was brought jarringly back to rest in only $t'=1.4\ s$

Acceleration is the change in velocity of the object over a period of time

(a) Acceleration in his direction of motion

$\Rightarrow a=\dfrac{v-0}{t}\\\\\Rightarrow a=\dfrac{282}{5}\\\\\Rightarrow a=56.4\ m/s^2$

(b) acceleration opposite to his direction of motion i.e. deceleration is

$\Rightarrow a_d=\dfrac{0-v}{t'}\\\\\Rightarrow a_d=\dfrac{-282}{1.4}\\\\\Rightarrow a_d=-201.42 \ m/s^2\\\Rightarrow a_d=201.42\ \text{decelration}$