Answer
(a) The buoyant force on the diver in seawater is 699 N
(b) Since the diver's weight of 713 N is more than the buoyant force, the diver will sink.
Work Step by Step
(a) We can convert the volume to units of $m^3$ as:
$V = (69.6~L)(10^{-3}~m^3/L)$
$V = 0.0696~m^3$
We then find the buoyant force on the diver in seawater;
$F_B = \rho~V~g$
$F_B = (1.025\times 10^3~kg/m^3)(0.0696~m^3)(9.80~m/s^2)$
$F_B = 699~N$
The buoyant force on the diver in seawater is 699 N.
(b) We can find the weight of the diver as:
$weight = (72.8~kg)(9.80~m/s^2)$
$weight = 713~N$
Since the diver's weight of 713 N is more than the buoyant force, the diver will sink.