4.5. Friction http://www.ck12.org
a. Draw a force diagram for the wagon, labeling all forces.
b. Calculate the horizontal and vertical components of Nathan’s pull. Label them on your diagram (use
dotted lines for components so as not to confuse them with other forces).
c. Calculate the normal force acting on the wagon. (HINT: It is NOT equal to the weight! Use your FBD
above).
d. Calculate the force of friction on the wagon.
e. Calculate the horizontal acceleration of the wagon.- When the 20 kg box to the right is pulled with a force of 100 N, it just starts to move (i.e. the maximum value
of static friction is overcome with a force of 100 N). What is the value of the coefficient of static friction,μS? - A different box, this time 5 kg in mass, is being pulled with a force of 20 N and is sliding with an acceleration
of 2m/s^2. Find the coefficient of kinetic friction,μK. - The large box on the table is 30 kg and is connected via a rope and pulley to a smaller 10 kg box, which is
hanging. The 10 kg mass is the highest mass you can hang without moving the box on the table. Find the
coefficient of static frictionμS. - A block has a little block hanging out to its side, as shown: