Question

Dr. John Paul Stapp was 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 and (b) deceleration. Express each in multiples of g (9.80 m/s2 ) by taking its ratio to the acceleration of gravity.

Answer 1

Answer:

a) $a=5.7551 \times g$

b) $d=20.5539\times g$

Explanation:

Given:

• speed of rocket initially, $v_i=0\ m.s^{-1}$

• top speed of rocket after acceleration, $v=282\ m.s^{-1}$

• time taken to get to the top speed, $t_i=5\ m.s^{-1}$

• final speed of the rocket, $v_f=0\ m.s^{-1}$

• time taken to get to the final speed after reaching the top speed, $t_f=1.4\ s$

Now the acceleration:

$a=\frac{v-v_i}{t_i}$

$a=\frac{282-0}{5}$

$a=56.4\ m.s^{-2}$

Now as a fraction of gravity:

$a=\frac{56.4}{9.8}\times g$

$a=5.7551 \times g$

Now, the deceleration:

$d=\frac{0-282}{1.4}$

$d=201.4285\ m.s^{-2}$

Now as a fraction of gravity:

$d=\frac{201.4285}{9.8}\times g$

$d=20.5539\times g$