What is the density of a piece of quartz with a mass of 30g and a volume of 6cm^3

An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

Atorque acting on an object tends to produce a. equilibrium b. rotation c. linear motion d. velocity e. a center of gravity