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Apply: conservation of momentum

You might need: Calculator


A person applies a 20N force for 2seconds to a shopping cart with an initial momentum of 60kgms to slow it down.
A person walks and pushes a shopping cart. An arrow points to the right, in the direction the person walks, and a label reads external force of twenty Newtons for two seconds. An arrow points to the left over the shopping cart and reads negative sixty kilogram meters per second.
What is the change in momentum of the shopping cart?
Your answer should have one significant figure.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi