7. the system shown in the figure is in equilibrium.
a. what is the maximum value (mass) that a can have if the frictional force on the 40 n block cannot exceed 12.0 n?
b. what is the coefficient of static friction between the block and tabletop?

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will mar branliest

Apositive charge moves in the direction of an electric field. which of the following statements are true? check all that apply. check all that apply. 1.the potential energy associated with the charge decreases. 2. the electric field does positive work on the charge. 3. the electric field does negative work on the charge. 4. the potential energy associated with the charge increases. 5. the electric field does not do any work on the charge. 6. the amount of work done on the charge cannot be determined without additional information.