Published in Physics Education
A simple experiment is described to illustrate the effects of a centripetal force on a ball rolling in a circular path around a shallow dish. The force acts to move the ball in a circular orbit, it acts to increase the friction force on the ball and it acts to rotate the spin axis of the ball away from the horizontal.
Published in European Journal of Physics
A simple experiment is described where a metal ring was rotated in a vertical plane on a horizontal rod. The ring rotated about 100 times before coming to a stop, so the friction force on the ring remained very small. However, measurements of the rotation frequencies of the ring around the rod and around its centre of mass indicated that the ring w...
Published in Physics Education
An experiment is described where a metal nut was allowed to slide from the top to the bottom of a vertical wire loop. An interesting feature is that the normal reaction force on the nut decreases to zero and reverses direction before the nut reaches the bottom of the loop.
Published in Materials Research Express
This study investigated the dry sliding behaviour of fluorinated tetrahedral amorphous carbon (ta-C:F) coatings against uncoated 52100 steel at temperatures ranging from 25 °C to 300 °C. The ta-C:F coatings demonstrated significant reductions in both the coefficient of friction(COF) during the running-in stage and at steady state, particularly with...
Pri energijski obravnavi fizikalnih problemov imajo dijaki pogosto težave z izbiro opazovanega sistema, nerodna izbira pa lahko preprosto nalogo spremeni tudi v nerešljivo, še posebej pri nalogah, ki vključujejo trenje. Magistrsko delo obravnava učinkovitost uporabe infrardečih (IR) posnetkov kot dopolnilno gradivo pri obravnavi fizikalnih poskusov...
Published in European Journal of Physics
The friction force on a circular object rolling without sliding down an inclined plane is due to static friction. If the object commences in a sliding mode at the top of the incline, and if the incline angle is small, then a small additional sliding friction force arises to reduce the sliding speed of the contact point to zero if the incline is suf...
Published in European Journal of Physics
Falling accidents are very common and are sometimes fatal. A fatal fall could be accidental, suicidal or homicide and needs to be investigated. A simple model of falls from a balcony is presented, together with simulated experimental results obtained using a straight rod falling over a horizontal rail. The experiments involve basic mechanics and wo...
Published in Surface Topography: Metrology and Properties
Researchers are used to investigating the influence of surface topography on the frictional electrification of sliding triboelectric nanogenerators TENGs from the perspective of a single-stratum topography; however, a stratified feature has shared reality in closer relationships. Here, we characterize the stratified feature of the topographies for ...
Wire rope has different degrees of surface wear under long-distance transmission conditions, which leads to performance degradation and greatly threatens its safety and reliability in service. In this paper, friction and wear tests between the transmission wire rope and sheave under different sliding velocities (from 0.8 m/s to 1.6 m/s) were carrie...
Published in Physics Education
A loop-the-loop experiment is described to show how sliding friction affects motion of the ball. Conservation of energy can be used to explain the basic physics, but significant energy loss is observed in practice and expands the usefulness of this apparatus as a teaching tool.
