When you push a piece of chalk across a chalkboard, it sometimes screeches because it rapidly alternates between slipping and sticking to the board. Describe this process in more detail, in particular, explaining how it is related to the fact that kinetic friction is less than static friction. (The same slip-grab process occurs when tires screech on pavement.)

Juan created a chart to him study for a test. which headings best complete the chart? x: transparent objects y: opaque objects x: opaque objects y: transparent objects x: high frequency waves y: low frequency waves x: low frequency waves y: high frequency waves

A3030 cmcm wrench is used to loosen a bolt with a force applied 0.30.3 mm from the bolt. it takes 6060 nn to loosen the bolt when the force is applied perpendicular to the wrench. how much force would it take if the force was applied at a 3030 degree angle from perpendicular? a 3030 cmcm wrench is used to loosen a bolt with a force applied 0.30.3 mm from the bolt. it takes 6060 nn to loosen the bolt when the force is applied perpendicular to the wrench. how much force would it take if the force was applied at a 3030 degree angle from perpendicular?

An open cart is moving along a straight frictionless horizontal track. when rain starts falling vertically into the cart, what happens to the speed of the cart?