, we see that we can solve for L if we know T (since g is known).- B Because the block moves in a circular path, it must experience a centripetal
acceleration (that is, an acceleration directed toward the center of the
circle). Now, since the speed of the block is changing, it must also be
experiencing a tangential acceleration; in particular, because the block’s
speed is increasing, this tangential acceleration must be in the same
direction as the block’s velocity. Therefore, the total acceleration of the
block is the sum of the centripetal acceleration ac and the tangential
acceleration at. The figure below shows that this sum points upward and to
the left, so arrow B is best. - B From the equation F = qE, where q is the magnitude of the charge in the
electric field, we find that - C A magnetic field always does zero work (because the magnetic force
applied is perpendicular). Doing work means a positive change in kinetic