# Physics-momentum/impluse

hi

well i have two questions i don't understand how to solve and all.

1) The front of a 1400-kg car is designed to absorb the shock of a collision by having a "crumple zone" in which the front of 1.2m of the car collapses in absorbing the shock of a collision. if a car traveling 25.0m/s stops uniformly in 1.2m, (a)how long does the collision last, (b) what is the magnitude of the average force on the car, and (c) what is the acceleration of the car in g's?

2) A 0.15kg baseball is thrown with a speed of 20m.s It is hit straight back at the pitcher with a final speed of 22m/s. (a) what is the impulse delivered to the ball? (b) find the average forece exerted by the bat on the ball if the two are in contact for 2.0 X 10^-3 seconds.

Thanks in advance..i really don't understand these two problems

a) To decelerate from velocity V to zero in a distance X, you need acceleration rate a given by
a = V^2/2X. The time to decelerate it
T = V/a = 2X/V

b)F = M a

c) divide a = V2/(2X) by g = 9.8 m/s^2 for the acceleration in g's.

2) (a) Use the fact that the momentum change equals the impulse. Consider the change of sign of the velocity when calculating the momentum change.
(b) Average force = (Impulse)/(time force is applied0

ohh i get it! thanks

wait umm for the second one... i don't understand ..like i know the process but yet its not working out for me..

for instance for part a) i don't understand like how to get it..i mean i know you would do FT=MV and then i don't know what exactly is to be done with..

b) ummm impulse/time..so it would be .15(2)/2.0*10^-3..but then it doesnt come out to the answer in the back of the book..

1. 0
2. 6

## Similar Questions

1. ### Math

How do you solve second order initial value problems? I don't understand how would solve these questions..for example (d^2 y)/(dx^2 )=24x^2-10. When x=1, dy/dx = 3, and y = 5. Can anyone explain how?

these questions are for practice, they don't count as points, but i don't understand how to solve them.. can someone please explain them to me?? which function rule represents the data in the table below? input|1| 2| 3| 4|5
3. ### GENERAL CHEMISTRY

CALCULATE THE pH AND HYDROLYSIS IN 0.10 M AlCl3 SOLUTION.Ka = 1.2 X 10-5 FOR [Al(OH2)6]+3,OFTEN ABBREVIATED Al+3.TELL WHETHER pH IS ACID OR BASE.GIVE IONIC EQUATION. Help us a little by telling us how much you know to do and
4. ### Math

My child's teacher sent out questions to prepare for a big math test. He does not understand the questions well and I can't seem to get him to grasp it. I know the answer but could you show some easy methods or something, thank
5. ### Math

Please help me! I know I am not showing my work but I don't even know how to solve these! Please help me! Tell whether the given equation has the ordered pair as a solution. 1. y = 6x; (3,16) 2. y = -4x; (-2,8) 3. y = x - 3/4;
6. ### general

I really don't like the fact that you guys are skipping so many questions we need help here and were not getting it. i understand that no one knows everything but, please don't skip the questions its really hard when i need help
7. ### Algebra

I don't understand how to do this problems: Solve for the variable r, C=2PIr (PI is the pi symbol thing then r is next to it) and this problem solve for the variable l, S=B+1/2Pl please help :) When you solve for a variable, you
8. ### math-moneyfractions

i have some math questions that i really ,really,need help with asap if any body can explain some of these questions that will be great help.Ok here are 3 of the questions i am about to type now ok the first one says,whole 16