Question

4.4: Problems involving Friction 4. A heavy fridge magnet is sliding down a fridge door that has a height of 67.5 cm. The magnet takes 0.92 s to slide, starting from rest, from the top of the door to the bottom. The mass of the magnet is 230 g and the magnetic force holding it to the fridge door is 2.5 N. Using this information, calculate the coefficient of kinetic friction between the magnet and the door. (Hint: start by working out the acceleration.)

Answer 1

Salo to fm ba 1 mg 67.5cm from Force by magnet (magnetic force) fm = 2.50 Na Normal force (N= fm) time, t= 0.92 sec ha mass, m=230g (strats from rest) h= 1 at? 0.675 = {xax(0.92)? Cacceleration 1 ferong na mg-f='ma (0.230x 9.8) - (4x2-5) = x16 Colroad a=1.6 m/s 3 j = en 1.886 = 205 el la 0.75 coefficient of friction.