Question

Scientists are making plans to put a probe in orbit around Earth. They want the probe to enter the orbit shown below.

An illustration of the earth with a concentric circle around the earth with arrowheads in the counterclockwise direction. At the top of the circle is a black dot with a vector labeled Y away from the center of the circle, a vector labeled W toward the center of the circle, a vector tangent to the circle and clockwise labeled Z and a vector labeled X tangent to the circle and counterclockwise.
Which arrow shows the direction that the probe should be moving in order for it to enter the orbit?

W
X
Y
Z

Answer 1

X

The probe must have a tangential velocity perpendicular to the radius (not radially inward or outward). The orbit arrowheads show counterclockwise motion, so the tangential counterclockwise vector X is correct.