use newton's laws and kinematic equations

9. A particle travels in a circle of radius Hint at a constant speed of 20mm. What is the magnitude of the acceleration? 10. A child of mass 400 kg is in a roller coaster car that travels in a loop of radius 7.00 m. At point A the speed of the ear is 10.1} W's. and at point B, the speed is 10.5 We. Assume the child is not holding on and does not wear a seat belt. What is the force of the car seat on the mild at point A? . What is the forte of the car seat on the rJ'LiId at point B? e. What minimum speed is required to keep the ehild in his seat at point A? crew