1) A 35 N horizontal force pushes on a 3.3 kg mass resting on a horizontal surface. The surface exerts a friction force of 18 N against the motion. The acceleration of the 3.3 kg mass is ____ m/s^2.

2) An 78 kg man starts from rest and after 1.70 seconds is running at a speed of 13.0 m/s. The force needed for this man to get up to this speed in 1.70 seconds is ____ N.