1. A skateboarder with a mass of 70 kg is riding a skateboard on a smooth, frictionless surface. The skateboarder applies a constant force of 150 N in the positive x-direction by pushing against the ground. (a) Calculate the acceleration of the skateboarder and the skateboard. (b) If the skateboarder starts from rest, how long does it take to reach a speed of 10 m/s? (c) Once the skateboarder reaches a speed of 10 m/s, they encounter a slight incline with a constant net resistance force of 30 N opposing their motion. Determine the time it takes for the skateboarder to come to a stop.