A child is pushing another child (20 kg) on a skateboard with a horizontal force of 17 N [right]. The coefficient of friction is 0.15. Determine the acceleration of the child riding the skateboard.

one person pulls 90n one way and the other has 100n pulling the other way.

so the net force = 90 - 100 = -10n,

or the ans can be 10n if the picture shows -90n and 100n instead.

there are no contact forces mentioned on the list of choices that you've provided.

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle

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