4.17 Acceleration Due to Gravity
4.17 Acceleration Due to Gravity
- Describe the acceleration of falling objects due to gravity.
- Explain why falling objects with different masses accelerate at the same rate.
It’s a good thing this mountain climber’s safety gear is working, because it’s a long way down to the ground! If
he were to fall, he’d be moving really fast by the time he got there. The higher any object starts falling from
above Earth’s surface, the faster it’s traveling by the time it reaches the ground. Do you know why? The reason is
gravity.
Speeding up While Falling Down
Gravityis a force that pulls objects down toward the ground. When objects fall to the ground, gravity causes them
to accelerate.Accelerationis a change in velocity, and velocity, in turn, is a measure of the speed and direction of
motion. Gravity causes an object to fall toward the ground at a faster and faster velocity the longer the object falls.
In fact, its velocity increases by 9.8 m/s^2 , so by 1 second after an object starts falling, its velocity is 9.8 m/s. By 2
seconds after it starts falling, its velocity is 19.6 m/s (9.8 m/s + 9.8 m/s), and so on. The acceleration of a falling
object due to gravity is illustrated in theFigure4.31. For a more detailed explanation of acceleration due to gravity,
watch this video: