Afarmhand pushes a bale of hay 3.9 m across the floor of a barn. she exerts a force of 88 n at an angle of 25∘ below the horizontal. a how much work has she done?

Aparticle of mass m is placed in a one-dimensional box of length l. the box is so small that the particle’s motion is relativistic, so that e p2/2m is not valid. (a) derive an expression for the energy levels of the particle using the relativistic energy–momentum relation and the quantization of momentum that derives from connement. (b) if the particle is an electron in a box of length l 1.00 1012 m, nd its lowest possible kinetic energy. by what percent is the nonrelativistic formula for the energy in error?

Which symbol in the first law of thermodynamics represents the sum of the chemical and thermal energy stored in atoms and molecules? a. q b. w c. v d. u

A10.0 kg crate is pushed with a horizontal force of 40 n. the crate moves at a constant velocity of 3.0 m/s. what is the value of the friction force on the crate? 10 n 100 n 40 n 70 n