Given that the system is motionless and that the tensional force is constant throughout the rope, we know that the weights on the platform must balance the weight of the mass. Given that the mass weights 2kg and each weight is 0.5kg, we can determine the number of weights required by dividing 2kg/0.5kg = 4 weights. Note that we can neglect the weight of the pulley in this problem; while this is usually the case on the MCAT as well, be sure to double check.

For acceleration to be zero, the force  needs to equal the sum of the frictional force on the block and the gravitational force on the hanging block.

To then accelerate the system, an additional force is needed.

This is the additional force required. Thus the total force required is:

Since the two vectors are perpendicular, they form a right triangle with the vector sum. Therefore, we simply use the Pythagorean theorem to solve for the sum.

The two vector components' directions determine the vector sum's direction as well. Since the components are north and east, the resultant vector is roughly northeast.

Newton's first law indicates that an object in motion will "want" to remain in motion at constant velocity unless it is acted on by a net force. In this case, Newton's first law is the only reasonable answer since in space, it is assumed there is no frictional or gravitational forces acting on the shuttle. Newton's second law can be described using the equation . Note that his first law is just a special case of the second law, where . Snell's law describes the interaction between waves and different media. Kirchhoff's laws involve charge conservation within circuits. Pascale's principle indicates that pressure exerted within a fluid is exerted equally in all directions. 

Since the block is moving to the right, we know that the frictional force is acting to the left. Also acting to the left is the gravitational force on the hanging block. Since it is a constant velocity of , we know that acceleration is zero and the downward force on the hanging block plus the frictional force is exactly equal to the force . Add the two forces.

The force that translates to the entire system is that of gravity acting on the mass hanging over the ledge.



140N is the total force acting on the system, which has a mass equal to both blocks combined (65 kg + 14 kg = 79 kg). We can find the acceleration using Newton's second law.

Newton’s second law can be used in combination with the spring force equation to solve for the acceleration of the system. Remember that any force, whether it is kinematic, electrical, or gravitational, is equal to Newton’s second law. 

F_spring = kx = ma_system

If the rope can only withstand 800N of force, we can solve for the mass of the object which would result in this maximum force when hanging from the rope.

The equation for force is  This shows that by increasing the man's mass, his force will increase after jumping from the plane.

All other options will result in a decreased acceleration when falling. Falling with his stomach downward increases the surface area of the diver, which increases his air resistance. A parachute will also increase the air resistance and surface area. If the plane is descending when he jumps, his time to reach terminal velocity will be reduced, as he will already have an initial velocity in the downward direction.

To solve this problem use Newton's second law:

We are given the acceleration and the force, both in the horizontal direction. Using these values we can find the mass of the jet.