A boat starts moving across a river at velocity v perpendicular to the river bank. The boat encounters a current along the river of velocity u, as shown.
u
river
Which vector diagram shows the resultant velocity r of the boat?
A
B
с
D
u
A
r
u

Photoelectrons with a maximum speed of 6.50 x 107 m/s are ejected from a surface in the presence of light with a frequency of 6.75 x 1014hz. if the mass of an electron is 9.10 x 10-31 kg, calculate in joules the maximum kinetic energy of a single electron. 3.84 x 10-15 j 1.92 x 10-15 j 5.92 x 10-23 j 3.07 x 10-16 j