a) Centripetal force

a) a constant net force perpendicular to the velocity of an object causes it to travel in a circular path

centripetal force = for an object in circular motion → constant net force acting perpendicular to its direction of motion

• perpendicular to the direction of motion → no net work done → constant speed

linear velocity = velocity at a tangent to the circular path

• when angular velocity is constant → linear velocity ∝ radius

horizontal circular motion (road)

• centripetal force usually = friction + component of normal contact force

vertical circular motion (fairground ride)

• top of the ride

  • normal contact force decreases

  • N < mg

• bottom of the ride

  • normal contact force increases

  • N > mg