Question

Block 1 is resting on the floor with block 2 at rest on top of it. Block 3, at rest on a smooth table with negligible friction, is attached to block 2 by a string that passes over a pulley, as shown above. The string and pulley have negligible mass. (a) i. On the dot that represents block 1, draw and label the forces (not components) exerted on block 1. Each force must be represented by a distinct arrow starting on, and pointing away from the dot. Draw the relative lengths of all arrows to reflect the relative magnitudes of the forces. ii. On the dot that represents block 2, draw and label the forces (not components) exerted on block 2. Each force must be represented by a distinct arrow starting on, and pointing away from the dot. Draw the relative lengths of all arrows to reflect the relative magnitudes of the forces. (d) On the axes below, sketch graphs of the velocity and the acceleration of block 2 after block 1 has been removed.

Answer 1

The forces exerted on Block 1 are the gravitational force and the normal force. The forces exerted on Block 2 are the tension in the rope, the gravitational force, and the force of block 3. The velocity graph will show an increasing velocity and the acceleration graph will show a constant acceleration.

Step-by-step explanation:

For Block 1:

The forces exerted on Block 1 are the gravitational force (downward) and the normal force exerted by the floor (upward). The normal force is equal in magnitude and opposite in direction to the gravitational force. Therefore, we can represent the forces on Block 1 with two arrows of equal length pointing in opposite directions.

For Block 2:

The forces exerted on Block 2 are the tension in the rope (upward), the gravitational force (downward), and the force of block 3 pulling it to the right (to the left on the diagram). The tension in the rope is equal in magnitude and opposite in direction to the force of block 3. Therefore, we can represent the forces on Block 2 with three arrows of equal length pointing in different directions.

On the velocity graph:

After Block 1 is removed, Block 2 will accelerate to the right. Thus, the velocity graph will show a positive slope indicating an increasing velocity over time.

On the acceleration graph:

The acceleration of Block 2 will remain constant. Therefore, the acceleration graph will show a horizontal line at a constant value.

Answer 2

The forces acting on block 1 are its weight and the normal force from the floor. The forces acting on block 2 are its weight, tension in the string, and the normal force from the contact with block 1. After block 1 is removed, block 2 will experience a downward acceleration.

Step-by-step explanation:

In this scenario, block 1 is resting on the floor, so the forces acting on it are its weight (downward) and the normal force from the floor (upward). These two forces will have the same magnitude.

On block 2, the forces acting on it are its weight (downward), tension in the string (upward), and the normal force from the contact with block 1 (downward). The weight of block 2 is greater than the tension in the string and the normal force, so the net force on block 2 is downward.

After block 1 is removed, block 2 will experience a downward acceleration due to the net force acting on it. The velocity and acceleration graphs of block 2 will show a linear increase in the magnitude of acceleration and a constant positive velocity.