A 40-kg girl is running through the supermarket and jumps onto a stationary shopping cart full of groceries that has a total
mass of 80-kg. They roll away together at a speed of 7 m/s.
How fast must she have been running before the collision?
m/s

answer: i'm not sure which is which for i get confused on it all the time but i can tell you that the answer lies with the convex and concave devices. i hope this you. have a good day and best of luck to you!

explanation:

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg