Si base unit used to measure the amount of a substance

In which of the following cases is work being done on an object? question 2 options: pushing against a locked door carrying a box down a corridor pulling a trailer up a hill suspending a heavy weight with a strong chain

What are known as the properties of substances that describe a substance et does not change that substances?

Auniform solid cylinder with a radius of 10 cm and a mass of 3.0 kg is rotating about its center with an angular speed of 33.4 rpm. what is its kinetic energy?