Which statement is true about the thermal energy of an object? Choose the correct answer. 1). Thermal energy is the internal potential energy of an object. 2). Thermal energy is the heat that is transferred in and out of an object. 3). Thermal energy is the sum of kinetic and potential energy of an object. 4). Thermal energy is the internal kinetic energy of the molecules of an object.

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 .