Name
Period
Date
Balanced Forces Worksheet 5
1. Draw a force diagram of the ball in each case. Write an equation for the vertical
forces acting and then calculate the tension in each cable.
Case A
Case B
5.0 kg
5.0 kg
35
35
2. An object is hung from a cable as in the diagram above. It has a weight of 25 N.
a. Draw and label the forces b. Write an equation for the forces and
(not components) that act
components that act vertically and then calculate
on the object.
the tension in the cable. If you need to draw
anything besides what you have shown in part
(a) to assist in your solution, use the space
below. Do NOT add anything to part (a).
c. Suppose the cable only deflects 5.0°. How would the new tension compare to
the tension found in (b) (smaller, larger, the same) and why? Calculate this new
tension to confirm your reasoning.
Balanced Forces Worksheet 5
page 2

FA
30.
3. The box on the frictionless ramp above is held at rest by the applied force. The
weight of the box is 100. N.
a. On the box below, draw
b. Write an equation for the forces and
and label the forces (not
components that act parallel to the incline and
components) that act on
then calculate the magnitude of the applied
the box.
force. If you need to draw anything besides
what you have shown in part (a) to assist in your
solution, use the space below. Do NOT add
anything to part (a).
200. N
m
4. In a modified Atwood’s machine, a 75 N force of
kinetic friction between the 200. N box and the
surface results in the system moving at constant
velocity.
a. On the system figure below, draw and label a
force diagram of the system as a whole.
200. N
Constant
Velocity
b. Write an equation for the horizontal
forces acting on the system and then
calculate the unknown hanging mass.
m?
Balanced Forces Worksheet 5
5. A man pulls a 50. kg box at constant
speed across the floor. He applies a
200. N force at an angle of 30. .
a. Draw and label the forces (not
components) acting on the box.
page 3
.
In parts (b) and (c), if you need to draw anything besides what you have shown in part
(a) to assist in your solution, use the space below. Do NOT add anything to part (a).
b. Write an equation for the forces and c. Write an equation for the forces and
components that act vertically on
components that act horizontally on the
the box. What is the value of the
box. What is the value of the frictional
normal force?
force opposing the motion?
The string breaks as he pulls the box across the floor.
d. Draw a new force diagram for the
e. Describe the new motion of the box
box after the string breaks.
after the string breaks. Explain why.
Balanced Forces Worksheet 5
page 4
6. Two masses hang from two strings as in the diagram. The


forces of tension in the strings are FT 1 and FT 2 .
a. On the system figure below, draw a force diagram of the
system of two masses. Write an equation for the vertical

forces acting on the system and then calculate FT 1 .

FT 1
7.0 kg
A

FT 2
4.0 kg
B
7.0 kg
A
4.0 kg
B
b. On the figures below, draw a force diagram for each mass individually. Write a
separate equation for the vertical forces acting on each mass and then calculate


FT 2 acting on each mass. ( FT 2 must be the same in both cases since it is only
one string!)
7.0 kg
A
4.0 kg
B
Balanced Forces Worksheet 5
page 5
55. kg
10. kg
7. Consider the modified Atwood’s machine sitting at rest as in the diagram above.
a. On the system figure below,
draw a force diagram of the
system as a whole.
b. Write an equation for the horizontal forces
acting on the system. What force of static
friction between the box and the surface is
required for the system to stay at rest?
c. Draw a separate force diagram for each mass.
d. Write an equation for the horizontal
forces acting on the 55 kg mass and
calculate the tension in the string.
e. Write an equation for the vertical forces
acting on the 10. kg mass and calculate
the tension in the string.