If the magnetic flux through a certain region is changing with time: a. a current must flow around the boundary
b. a magnetic field must exist at the boundary
c. an electric field must not exist at the boundary
d. an emf must exist around the boundary energy must be dissipated as heat

The x-coordinate of a particle in curvilinear motion is given by x = 3.1t3 - 4.9t where x is in feet and t is in seconds. the y-component of acceleration in feet per second squared is given by ay = 2.3t. if the particle has y-components y = 0 and vy = 5.0 ft/sec when t = 0, find the magnitudes of the velocity v and acceleration a when t = 1.8 sec. sketch the path for the first 1.8 seconds of motion, and show the velocity and acceleration vectors for t = 1.8 sec. answers: v = ft/sec a = ft/sec2

It is really hard for me right know

Which planet do you think would be easiest for humans to colonize some day?