Answer is: the mass of the body is 35 kg.
Newton's second law of motion: F = m · a.
F - force applied.
m - mass of the object receiving the force.
a - the acceleration of the object.
F = 350 N.
a = 10 m/s².
m = ?
m = F ÷ a.
m = 350 N ÷ 10 m/s².
m = 35 kg.
One newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in direction of the applied force.
