Final answer:
a. The magnitude of the net force on the rock is 108 N, directed downward. b. The gravitational force on the rock is 132.3 N, also directed downward. c. The air resistance acting on the rock is -24.3 N, directed upward.
Step-by-step explanation:
a. The magnitude of the net force on the rock can be found using Newton's second law, which states that force is equal to mass multiplied by acceleration. In this case, the mass of the rock is 13.5 kg and the acceleration is 8.0 m/s². Therefore, the net force on the rock is F = m * a = 13.5 kg * 8.0 m/s² = 108 N. The direction of the net force is given as downward.
b. The gravitational force on an object can be calculated using the formula F = m * g, where m is the mass of the object and g is the acceleration due to gravity. In this case, the mass of the rock is 13.5 kg and the acceleration due to gravity is 9.8 m/s². Therefore, the gravitational force on the rock is F = m * g = 13.5 kg * 9.8 m/s² = 132.3 N. The direction of the gravitational force is also downward.
c. To find the air resistance acting on the rock, we need to consider that the net force on the rock is the vector sum of the gravitational force and the air resistance. Since the net force is equal to the mass multiplied by the acceleration, we can rearrange the equation to find the air resistance: air resistance = net force - gravitational force = 108 N - 132.3 N = -24.3 N. The negative sign indicates that the air resistance is acting in the opposite direction of the net force, which in this case is upward.