The Student Room Group

resultant force

hi, so i was given a paper and it had a question on average resultant force that the teacher did not teach and since i am currently on spring break i was hoping someone could explain th e concept to me.
the question basically states that a car travelling at 20m/s has a 70kg dummy in the passenger compartment. the car hits a barrier and comes to a stop. the passenger compartment comes to a rest in 0.20 seconds. the air bag and seatbelt and airbag bring the dummy to rest at an average deceleration of 80m/s2 . it then asks what the average resultant force applied to the dummy is.

if anyone can explain it to me i'd be really glad, thanks
Original post by notthemonalisa
hi, so i was given a paper and it had a question on average resultant force that the teacher did not teach and since i am currently on spring break i was hoping someone could explain th e concept to me.
the question basically states that a car travelling at 20m/s has a 70kg dummy in the passenger compartment. the car hits a barrier and comes to a stop. the passenger compartment comes to a rest in 0.20 seconds. the air bag and seatbelt and airbag bring the dummy to rest at an average deceleration of 80m/s2 . it then asks what the average resultant force applied to the dummy is.

if anyone can explain it to me i'd be really glad, thanks


F=ma (Newton's second law)
you're given the mass of the dummy and the acceleration of the dummy (deceleration is just acceleration in the opposite direction to the original velocity)
Original post by Joinedup
F=ma (Newton's second law)
you're given the mass of the dummy and the acceleration of the dummy (deceleration is just acceleration in the opposite direction to the original velocity)


Would the answer be
-6300N? :hmmmm:
I've added the two decelerations and multiplied with the dummy mass...
Original post by Spannerin'moi
Would the answer be
-6300N? :hmmmm:
I've added the two decelerations and multiplied with the dummy mass...

No, here is the question:
https://www.cambridgeinternational.org/Images/425640-june-2016-question-paper-41.pdf

Using F = ma, the resultant force on the dummy is mass of dummy x deceleration of dummy = 70 x 80 = 5600 N
No need to include a sign
Original post by BobbJo
No, here is the question:
https://www.cambridgeinternational.org/Images/425640-june-2016-question-paper-41.pdf

Using F = ma, the resultant force on the dummy is mass of dummy x deceleration of dummy = 70 x 80 = 5600 N
No need to include a sign

:ta: for the link and explanation! :smile:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you