53. A 70-kg stunt artist rides in a rocket sled which slides along a flat inclined surface. At an instant when the sled’s acceleration has a horizontal component of 6.0 m/s2 and a downward component of 2.8m/s2, what is the magnitude of the force on the rider by the sled?
a. 0.83 kN
b. 0.98 kN
c. 0.65 kN
d. 0.68 kN
e. 0.72 kN