Recall the relationship of distance and acceleration:e Diemm dat, where a g=9.8 m/s, and d = 4 ft = 1.22 m b. Rearrange the equation to solve for time, t. Your equation: f= Your calculation: t = 2 Estimate the velocity of the victim just an instant before hitting the floor. a. Recall the relationship of velocity and acceleration: v=at, where a=g=9.8 m/s2, and t is the value from above. b. Solve for velocity, v. Your equation: v= Your calculation: v= m/s 3. Estimate the stopping acceleration of the victim's head upon hitting the floor. Assume the stopping time to be about 0.004 seconds. a. Use the equation from 2.a. above, but this time solve for a: Av=a t, where Av is the change in velocity from the value (in the previous section, 2.b.) to zero, which is effectively the same as the value from above, and = 0.004s b. Rearrange the equation to solve for acceleration, a. Your equation: a = Your calculation: a = c. How many "gees" is that? Divide this number by gravitational acceleration. Your calculation: a = d. How does this value compare to the "fatal" acceleration of 30 gees? sec Stenunch m/s gees MINK 4. The average weight for 11 month old children (boys or girls) is 22 lbs, which is exactly equal to 10 kg. Estimate the momentum of the victim just an instant before hitting the floor. a. Recall the equation for momentum: p=mv, where v is the value from 2.b. above. b. Solve for velocity, p. Your equation: p= Your calculation: p= 5. Note that change in momentum at impact is equal to the "impulse": Change in momentum = Ap= Impulse = Force x Time = Ft. a. Calculate the force of impact from the Impulse equation: Rearrange the impulse equation and solve for force, F. Since force = mass x acceleration, calculate the force of impact using the mass of the victim and the acceleration you found in section 3.b. Your equation: F= Your calculation: F= b. How do your two force calculations compare? kg-m/s N 6. The momentum and impulse cannot be changed, but if the amount of time of impact could be somehow made longer, then the force of the impact would be less. This can be accomplished by padding the child's head, with a soft cap or something. Assuming a soft cap could have slowed the time of impact to 0.04 seconds, how is the force of impact changed? a. Use the rearranged impulse equation you derived in 5.a. to find the force of impact for t=0.04 s. Your equation: F= Your calculation: F= b. What is the deceleration of the 10 kg child with this amount of acting force? Your calculation: a = c. How many gees is this equivalent to? Your calculation: a = d. Was the soft cap enough to potentially have saved the child's life? N m/s gees