A sled glides onto a long flat stretch of snow at a good speed and slips slowly to a stop.
Nothing lifted it; nothing stretched. Its kinetic energy has left the motion.
The energy seems lost. Where is it?
Right after the stop, the runners are slightly warm. So is the snow along the track.
Friction acted on the sled the whole way, and the rubbing warmed both surfaces.
This process is called dissipation.
A box slid across a carpet stops the same way: the box's base and the carpet warm, and the box's kinetic energy spreads as thermal energy.
A cyclist who stops pedaling on a level road slows the same way: air resistance converts the bike's mechanical energy into thermal energy spread through the air, the bike, and the rider.
A hockey puck glides along rough rink ice and stops. Say where its kinetic energy went.
Friction acts on the puck along the whole glide.
Friction converts the puck's kinetic energy into thermal energy.
The thermal energy spreads into the puck, the ice, and the surroundings.
The puck's kinetic energy is now thermal energy in the puck, the ice, and the surroundings: it dissipated.
A skateboard rolls along a level sidewalk, slows, and stops. What happened to its kinetic energy?
Dissipated energy is not destroyed, and it has not vanished: it is thermal energy now, spread too thin to see as motion.
An e-scooter coasts on a level path with its motor off and slows, with no brakes applied. Explain what happens to its kinetic energy.
Air resistance and friction act on the coasting scooter.
The two forces convert the scooter's kinetic energy into thermal energy.
The thermal energy spreads into the air, the scooter, and the path.
The scooter's kinetic energy dissipates: it spreads as thermal energy into the air, the scooter, and the path.
A cafeteria tray slides to a stop on a long counter. Dov says: 'The tray's base and the counter are slightly warmer than just before the slide.' Is he correct?
This topic tracks how much thermal energy appears, never how warm anything gets.
Friction converts a wagon's mechanical energy into thermal energy that spreads into the wheels, the ground, and the surroundings. What is this process called?
A subway train brakes to a smooth stop on level track. What happens to its kinetic energy?
In real motion, which pair of forces converts mechanical energy into thermal energy?
A shuffleboard disk slides to a stop on a rough lane. Flor looks for the disk's kinetic energy afterward. Where is it?