A 9.0kg block slides in a straight line. The velocity of the block as a function of time is displayed in the vxt graph, as shown in the gure. Calculate the average net force F 1x on the block for the time i] Calculate the average net force sz on the block for the time i] Calculate the average net force F3x on the block for the time i] Calculate the average net force F4x on the block for the time i] Calculate the average net force st on the block for the time i] t = 6 to 7 s