Question

Please help me! In a collision, Kara Less who was traveling at 11 m/s while texting in her 1300 kg car, is struck by another vehicle and finds herself and her phone suddenly moving 2.5 m/s in the opposite direction. What impulse does she experience? SHOW WORK

Answer Choices

A. -12,000
B. -14,000
C. -16,000
D. -18,000

Answer 1

D. -18,000

Step-by-step explanation:

Let's define impulse :

• Impulse is defined as the product of Force ( N ) applied on the body and the time of impact ( s ) or
• The change in momentum

hence in this question ,

kara is initially moving with the :

• velocity
  `v_(i)` = 11
  `ms^(-1)`

• finally moving with velocity
  `v_(f)` = -2.5
  `ms^(-1)` (minus as she moves in the opposite direction )

therefore the initial momentum
`p_(i)` =
`m*v_(i)  = 1300*11 = 14300 kgms^(-1)`

and the final momentum
`p_(f)` =
`m*v_(f) = 1300*-2.5= 3250 kgms^(-1)`

thus the change in momentum :
`p_(f)` -
`p_(i)`

= -3250-14300 = -17550
`kgms^(-1)` ≅ -18000
`kgms^(-1)`