Astudent pushes a 12.0 kg box with a horizontal force of 20 n. the friction force on the box is 9.0 n. which of the following is the best approximation of the box’s acceleration?

The acceleration of the box its 0,91 m/s²

Explanation:

According to Newton first law, the force applyed to some object its equal to the mass of the object plus the acceleration of the same object.

   F=m.a ; clearing the acceleration of the equation ⇒ a=F/m

  Now in the problem its apeared the friction force and according to de phsysics definition its a force thats its against of movement.

  So the force its going to be equal to F= 20N - 9N.

 Replacing in the equation a=(20N - 9N)/12kg.

 Solving ⇒ a ≅0, 91 m/s²

what was the acceleration of the 2 kg cart?

⇒ 16.0 cm/s2

what was the acceleration of the 4 kg cart?

⇒ 8.1 cm/s2

what was the acceleration of the 6 kg cart?

⇒ 5.3 cm/s2