-- 6 people all trying to push a car out of snow
-- a Tug-o-War with 30 people of different sizes pulling on each end of the rope
-- you and your sister both pulling on the same doll (or Transformer)
-- lifting a book up from the table to a high shelf
taking a book down from a high shelf to the table
(one force is you; another force is gravity)
-- grabbing your big dog by his collar and trying to bring him inside
-- three people at the table all grab the ketchup bottle at the same time
Answer:
Right now I have three.
Explanation: Thanks for the points luv ^-^.
Answer:
a)
b) 
Explanation:
The net force on the car must produce the centripetal acceleration necessary to make this circle, which is 
. At the top of the circle, the normal force and the weight point downwards (like the centripetal force should), while at the bottom the normal force points upwards (like the centripetal force should) and the weight downwards, so we have (taking the upwards direction as positive):
Which means:
The limit for falling off would be 
, so the minimum speed would be:
Momentum = m • v
Original momentum = m • 10 m/s north
Final momentum = m • 15 m/s north
Change = m • (15 - 10) m/s north
Change = m • +5 m/s north
Change = +60 kg-m/s north
