1. A runner moving at a speed of 8.8 m/s rounds a bend with a radius of 25 m. What is the centripetal acceleration of the runner? 2. Racing on a flat track, a car takes 5.5 s to round a curve with a radius of 56 m. What is the centripetal acceleration of the car? 3. A physics student swings a small rubber ball attached to a string over her head in a horizontal, circular path. The piece of string is 2.0 meters long and the ball makes 2 revolutions per second. What is the ball's centripetal acceleration? Ax 2r v = = 2rf At T Centripetal Acceleration 122 Fnet c mac m r 1 T(period) f (frequency) Centripetal Force 1. A.013-kg rubber stopper is attached to a 0.93-m string. The stopper is swung in a horizontal circle, making one revolution in 0.75 s. a) Find the tension force exerted by the string on the stopper? b) If the mass is doubled, but all other quantities remain the same, what would be the effect on the velocity, acceleration and force? c) If the radius is doubled, but all other quantities remain the same, what would be the effect on the velocity, acceleration, and force? d) If the period of revolution is half as large, but all other quantities remain the same, what would be the effect on the velocity, acceleration and force? 2. A 200 kg car moving at 10 m/s is going around a circular track with a radius of 25m. a) What is the cars centripetal acceleration? b) What agent exerts a force on the car? c) Calculate a numeric value for this force. 3. A 2 kg ball moves at 2 m/s in a horizontal, circular path with a radius of 0.5 m. a) What is the centripetal acceleration of the ball? b) What is the tension in the string? Ax 2r v = = 2rf At T Circular Motion - HW 1 Centripetal Acceleration 1 Fnet c mac m T(period) = f (frequency) Name 1. A race car makes one lap around a race track of radius 50 meters in 9.0 seconds. a) What is the average speed? b) What was the car's centripetal acceleration? 2. A car goes around a curve at 20 m/s. The radius of the curve is 50 meters. Calculate the centripetal acceleration of the car. 3. A student swings a rubber ball attached to a string over his head in a horizontal, circular path. The piece of string is 1.0 meters long and the ball makes 2 complete circles each second. a) What is the average speed of the ball? b) What is the ball's centripetal acceleration? Centripetal Force 1. What is the centripetal force acting on a 1.5-kg object moving in a circular path with a centripetal acceleration of 18 m/s?