[填空题]
A jet aircraft is accelehc y5s 3x4xps ) tqn9ocns)6b4b)h+ 2nfa i2h3k*ry djrating at 3.5 $\mathrm{~m} / \mathrm{s}^{2}$ at an angle of 45$^{\circ} $ above the horizontal. What is the total force that the cockpit seat exerts on the 75$-\mathrm{kg} $ pilot? N $^{\circ} $
