forces and free body diagrams examples

box is sliding across level floor and coming to a stop

• friction, gravity, and normal force

• not at equilibrium because object is slowing down and forces are not equal

ball is being whirled in a horizontal circle over your head

gravitational and tension force

• not equilibrium because the ball is turning towards the center

object oscillating vertically on a spring

• gravitational and spring force

• not equilibrium because object changes speed and direction as it oscillates

box sliding down constant velocity down a smooth ramp

• friction, normal, and gravitational

• equilibrium because forces are equal and constant velocity

a car is moving at a constant speed around a level curve. are the forces in the car at equillibrium?

• the vertical forces (normal and gravitational) are at equilibrium

• the horizontal forces (only tension) are not at equilibrium - because the car is moving in a circular path and accelerating as it turns towards the center of the circle - changing the direction of the velocity, not the maginitude.