Convection currents in air and water occur because warm fluids are less dense than cold fluids cold fluids are less dense than warm fluids the molecules of warm fluids bump into the molecules of cold fluids electromagnetic waves move the air or water

It's a snowy day and you're pulling a friend along a level road on a sled. you've both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. you've been walking at a steady 1.5m/s, and the rope pulls up on the sled at a 32 ∘ angle. you estimate that the mass of the sled, with your friend on it, is 65 kg and that you're pulling with a force of 80 n .