Respuesta :
Answer:
Procedures 4 and 5.
Explanation:
Both would cause the box to move up.
4, it becomes lighter
5, the other becomes heavier, pulling it down, causing box one to go up
Since we seek the action of force to push up box 1, the students observes an unbalanced upward force on Box 1 in procedures 4 and procedure 5.
In what procedures did students observe an unbalanced upward force on Box 1?
Generally, In procedure 4 we added another mass to the box two, therefore, causing box one to experience an upward force.
Therefore, students observe an unbalanced upward force on Box 1 in procedure 4.
Procedure 5 we remove masses from box 1 resulting in box 2 becoming heavier, pulling it down.
Therefore, students observe an unbalanced upward force on Box 1 in procedure 5.
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