W mg x y fx fy f T11 (a) A projectile in flight with velocity µ relative to the ground (b) Freebody diagram for the projectile In still air, the air In this example the baseball was given an initial velocity of 50 m/s at an angle of 35° above the xaxis You can see that both the range of theWithout the effect of air resistance, each object in free fall would keep accelerating byHooke's law A ideal spring has an equilibrium length If a spring is compressed, then a force with magnitude proportional to the decrease in length from the equilibrium length is pushing each end away from the other If a spring is stretched, then a force with magnitude proportional to the increase in length from the equilibrium length is pulling each end towards the other
Chapter One
