Answer Happy

A bicyclist rides 3.15 km due east, while the resistive force from the air has a magnitude of 6.61 N and points due west. The rider then turns around and rides 3.15 km due west, back to her starting point. The resistive force from the air on the return trip has a magnitude of 6.61 N and points due east. Find the work done by the resistive force during the round trip.
A 54.7-kg skateboarder starts out with a speed of 1.64 m/s. He does 89.7 J of work on himself by pushing with his feet against the ground. In addition, friction does -284 J of work on him. In both cases, the forces doing the work are non-conservative. The final speed of the skateboarder is 8.40 m/s. (a) Calculate the change (PEF - PEo) in the gravitational potential energy. (b) How much has the vertical height of the skater changed? Give the absolute value. (a) Number i 89.7 (b) Number -3.9 Units Units
The skateboarder in the drawing starts down the left side of the ramp with an initial speed of 6.1 m/s. Neglect nonconservative forces, such as friction and air resistance, and find the heighth of the highest point reached by the skateboarder on the right side of the ramp. i