Question

coefficient of friction worksheet

1. a hockey puck has a coefficient of kinetic friction of \\( \mu _ { k } =.10 \\). if the puck feels a normal force \\( ( f _ { n } ) \\) of 5 n, what is the frictional force that acts on the puck?
2. suppose a 10 n force is applied to the side of a 4.0 kg block that is sitting on a table. the block experiences a frictional force against the force that is applied.

a. draw a force diagram for the block.
b. what is the weight of the block \\( ( f _ { g } ) \\)?
c. what is the normal force on the block \\( ( f _ { n } ) \\)?

Explanation:

Step1: Calculate the weight of the block

The formula for weight is \(F_G = mg\), where \(m = 4.0\space kg\) and \(g= 9.8\space m/s^{2}\).
\(F_G=4.0\times9.8\)

Step2: Determine the normal force

Since the block is on a horizontal table and there is no vertical acceleration, by Newton's second law in the vertical direction \(F_N - F_G=0\) (because \(a_y = 0\) and \(F_{net,y}=ma_y\)). So \(F_N=F_G\).

Answer:

b. \(F_G = 39.2\space N\)
c. \(F_N = 39.2\space N\)