Exam 6: Circular Motion and Other Applications of Newtons Laws

A sample of blood is placed into a centrifuge of radius 15.0 cm.The mass of a red corpuscle is 3.0 × 10−¹⁶ kg,and the centripetal force required to make it settle out of the plasma is 4.0 × 10−¹¹ N.At how many revolutions per second should the centrifuge be operated?

A car travels around an unbanked highway curve (radius 0.15 km)at a constant speed of 25 m/s.What is the magnitude of the resultant force acting on the driver,who weighs 0.80 kN?

A 50-kg child riding a Ferris wheel (radius = 10 m)travels in a vertical circle.The wheel completes one revolution every 10 s.What is the magnitude of the force on the child by the seat at the highest point on the circular path?

What is the net force on a 10-kg solid steel sphere falling in air at terminal speed?

A 4.0-kg mass attached to the end of a string swings in a vertical circle of radius 2.0 m.When the string makes an angle of 35° with the vertical as shown,the speed of the mass is 5.0 m/s.At this instant what is the magnitude of the force the string exerts on the mass?

A car enters a level,unbanked semi-circular hairpin turn of 300 m radius at a speed of 40 m/s.The coefficient of friction between the tires and the road is μ = 0.25.If the car maintains a constant speed of 40 m/s,it will

A car travels along the perimeter of a vertical circle (radius = 0.25 km)at a constant speed of 30 m/s.What is the magnitude of the resultant force on the 60-kg driver of the car at the lowest point on this circular path?

A stunt pilot weighing 0.70 kN performs a vertical circular dive of radius 0.80 km.At the bottom of the dive,the pilot has a speed of 0.20 km/s which at that instant is not changing.What force does the plane exert on the pilot?

The coefficient of static friction for the tires of a race car is 0.950 and the coefficient of kinetic friction is 0.800.The car is on a level circular track of 50.0 m radius on a planet where Compared to Earth's )If the car is to be able to travel at the same speed on the planet as on Earth,the radius of the track on the planet must be ____ times as large as the radius of the track on Earth.

A car enters a level,unbanked semi-circular hairpin turn of 100 m radius at a speed of 28 m/s.The coefficient of friction between the tires and the road is μ = 0.800.If the car maintains a constant speed of 28 m/s,it will

A hornet circles around a pop can at increasing speed while flying in a path with a 12-cm diameter.We can conclude that the hornet's wings must push on the air with force components that are

A rock attached to a string swings in a vertical circle.Which free body diagram could correctly describe the force(s)on the rock when the string is in one possible horizontal position?

A split highway has a number of lanes for traffic.For traffic going in one direction,the radius for the inside of the curve is half the radius for the outside.One car,car A,travels on the inside while another car of equal mass,car B,travels at equal speed on the outside of the curve.Which statement about resultant forces on the cars is correct?

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s.If the radius were changed to 1000 m,but the speed remained the same,by what factor would its centripetal acceleration change?

A student is sitting on the right side of a school bus when it makes a right turn.We know that the force of gravity acts downwards and a normal force from the seat acts upwards.If the student stays in place when the bus turns,we also know that there must be