Question 3 [12 marks]
a. As you push a block from rest across a rough surface, the frictional force changes. On the axis
given, sketch the frictional force as a function of the applied force. [4 points]
$f_k$
$F_{app}$
b. A block of mass 8.00 kg, sitting on a scale, starts from rest and begins to move vertically as a
force $F_o$ is applied as shown. During the motion, the reading on the scale is 65.0 N.
i. Is the block being accelerated? [2 points]
ii. Is the block/scale system rising or falling? [2 points]
iii. What is the acceleration of the block? [2 points]
iv. Is it possible to calculate the force $F_o$? Justify your answer. [2 points]
Scale
$F_o$