Adelivery company has unloaded a 21 kg crate in your driveway. the coefficient of static friction between the crate and the driveway surface is μs = 0.70. the coefficient of kinetic friction is μk = 0.60. in order to move the crate, you apply a horizontal force of magnitude f by pushing on it. as a result, the crate slides with an acceleration of 4.0 m/s2. what is the force f?

Scout feels ill one day before school. her mother puts a thermometer in her mouth and the temperature begins to climb to 100°f. what is happening between the cooler thermometer and scout's body? a) scout's body is applying a force to the particles in the thermometer. b) kinetic energy is being transferred from her mouth to the thermometer. c) potential energy is being lost by the thermometer and gained by scout's body. d) the potential energy stored in foods is converted to mechanical energy to raise the mercury in the thermometer.

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

What properties of a moving object are used in determining the object's energy of motion