1) Four children are trying to move a giant rock that is lying on the ground. The mass of the rock is m and the magnitude of the acceleration due to gravity is g. Each child attaches a rope to the rock and pulls on that rope with the same force magnitude (F) either horizontally, vertically, or at a 45.0 angle. For each case below, determine the magnitude of the force on the rock by the ground (a contact force) in terms of F, m, and/or g, given that the rock remains at rest. Note: The force on the rock by the ground is not the same as the gravitational force on the rock by the earth (a non-contact force). For the physical representation (part 2a), draw and label a free-body diagram for the rock in each case. As part of the reflection (part 4a), explain why the forces on the rock by the ground are not the same in each case. Case A Case B Case C Child 2 Child 2 Child 2 Child 3 Child 1 Child 1 Child 4 Child 1 Child 4 Child 4 Child 3 Child 3 2) The solution to this problem does not use the required solution format. To solve this problem, simply draw the free -body diagrams for the following situations. In the free-body diagrams, include a vector indicating the direction of the net force (unless it is zero) and another vector indicating the direction of the object's acceleration (unless it is zero). Include the force vectors (magnitude and direction) but do not include separate arrows for their components. A) You are riding a bicycle down a hill while applying the brakes and skidding to a stop. Assume that air resistance is negligible, but friction is not. B) You jump off a bridge with a bungee cord attached to your ankle, and the cord stretches. Assume air resistance is negligible. C) A rocket is accelerating straight up through the Earth's atmosphere. Assume that air resistance is not negligible. D) A meteoroid moves downward through the Earth's atmosphere. Its speed is decreasing. Assume that air resistance is not negligible.