What are four elements that are involved in the cycling of energy and matter on earth

The energy equivalent of the rest mass of an electron is

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 .

Acar going 10 m/s starts accelerating at a rate of 3 m/s2 for 4 seconds calculate the final velocity of the car