1. Raising and Lowering

2. 1

3. A box is lowered at constant velocity
A box is lowered at constant velocity. Does the acceleration depend on the velocity? What is the net force on the box? Draw a force diagram for the box.
Acceleration = rate of change in velocity = 0 for any size constant velocity (5 – 5 = 0, 10 – 10 = 0, etc.)
The net force = mass x acceleration = 0
velocity
Acceleration = 0

4. 2

5. A box is raised at constant velocity. Is the acceleration +, -, or 0
A box is raised at constant velocity. Is the acceleration +, -, or 0? What is the net force on the box? Draw a force diagram for the box.
Acceleration = rate of change in velocity = 0 since velocity does not change
The net force = mass x acceleration = 0
velocity
Acceleration = 0

6. 3

7. A box is lowered with uniformly increasing speed and more negative velocity. Is the acceleration +, -, or 0? Is the net force on the box, up, down or zero? Draw a force diagram for the box.
Acceleration is (-) since the velocity is becoming more negative
The net force = mass x acceleration which is downwards since acceleration is downwards.
acceleration
velocity

8. 4

9. A box is raised with uniformly increasing speed and more positive velocity. Does the acceleration depend on the velocity? Is the net force on the box, up, down or zero? Draw a force diagram for the box.
Acceleration is (+) since the velocity is becoming more positive
The net force = mass x acceleration which is upwards since acceleration is upwards.
acceleration
velocity

10. 5

11. A box is lowered with uniformly decreasing speed and less negative velocity. Draw a motion diagram for the box. Is the net force on the box, up, down or zero? Draw a force diagram for the box.
Acceleration is positive, e.g. velocity might change from -10 to -5, an increase of +5.
The net force = mass x acceleration which is upwards since acceleration is upwards.
acceleration
It takes a net upward force to slow the descent of the box.
velocity

12. 6

13. A box is raised with uniformly decreasing speed and less positive velocity. Draw a motion diagram for the box. Is the net force on the box, up, down or zero? Draw a force diagram for the box.
Acceleration is negative, e.g. velocity might change from +10 to +5, a change of -5.
The net force = mass x acceleration which is downwards since acceleration is downwards.
acceleration
velocity