A scientist finds Trophite fossils. According to the chart above, in what era and period was this rock layer deposited?

What is the function of the commutator in a dc motor? a. to spin the magnet b. to change direct current into alternating current c. to change alternating current into direct current d. to spin the wire coil

Many machines- including inclined planes such as ramps- increase the strength of the force put into the machine but decrease the distance over which the force is applied. true or false

Aball is thrown straight up into the air with a speed of 21 m/s. if the ball has a mass of 0.1 kg, how high does the ball go? acceleration due to gravity is g = 9.8 m/s^2. a. 22.5 m b. 20.0 m c. 25.0 m d. 17.5 m