Agirls walks 4 steps forward and then 3 steps backward. the girls distance walked is steps and her displacement is steps. a) 1, 7 b) 3, 4 c) 7, 1 d) 7, 7

The distance walked would be the total amount of her movement.  

4 steps+3 steps=7 steps

The displacement is how far from her original location the girl is.  

4 steps-3 steps=1 step.

C) 7, 1

Hope this helps!!

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied