A skateboarder of total mass pushes against the ground so that an average forward…
PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials
Problem
A skateboarder of total mass 60kg pushes against the ground so that an average forward force of 90N acts on the system. The rolling friction and air resistance together oppose the motion with a force of 30N along the same straight path. The skateboarder starts from rest and the push lasts for 3s.
Answer the following.
(i) Determine the net external force acting on the skateboarder + skateboard system.
(ii) Calculate the magnitude of the acceleration produced.
(iii) Find the speed of the skateboarder at the end of 3s.