Question

dr. john was a u.s air force officer who studied the effects of extreme deceleration on the human body. On December 10, 1954 he rode a rocket sled, accelerating from resr 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 and (b) deceleration. Express each in multiples of g (9.80 m/s2) by taking its ratio to the acceleration of gravity.

Answer 1

The value of accelerating the rocket sled from rest to 5 sec with the speed of,

`v_1=282ms^(-1)`

Thus, the acceleration of the rocket sled is,

`\begin{gathered} a=(v_1-0)/(5-0) \\ a=(282)/(5) \\ a=56.4ms^(-2) \\ a=5.8\text{g} \end{gathered}`

where g is the acceleration due to gravity.

`g=9.8ms^(-2)`

The rocket sled is declerated to the rest in 1.4 s from the speed v1,

Thus, the decleration of the rocket sled is,

`\begin{gathered} d=(0-v_1)/(1.4) \\ d=(-282)/(1.4) \\ d=-201.43ms^(-2) \\ d=-20.6g \end{gathered}`

Hence, the rocket sled is accelerated at 5.8g and decelerated at -20.6g.