A roller coaster is stationary at the top of a ramp. What is the kinetic and potential energy of the roller coaster?

A. potential energy: zero
kinetic energy: zero

B. potential energy: high
kinetic energy: high

C. potential energy: high
kinetic energy: zero

D. potential energy: zero
kinetic energy: high

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon

Hi , i am new here can anyone me out with this question why is space black after having so many shining objects like sun , moon , stars

The vector a? is 3.50 cm long and is directed into this page. vector b? points from the lower-right corner of this page to the upper-left corner of this page and has the components bx=-19.5 cm , by=25 cm. in the right-handed coordinate system, where the +x-axis directed to the right, the +y-axis toward the top of the page, and +z-axis out of the page, find the x-component of the vector product a? ×b? , measured in cm2.