# Kinematics Question: Falling object

• Catchingupquickly
In summary: In this case, the answer for part a) would be 38 m and part b) would be -27 m/s, both with a ±5% uncertainty.

## Homework Statement

Marian, who is standing on her balcony, is surprised by a pigeon and throws a flowerpot up in the air at 2.1 m/s. It takes 3.0 s for the flowerpot to smash to the ground. The flowerpot experiences acceleration due to gravity of 9.81 m/s [down].

a) How high is Marian’s balcony?

b) How fast was the flowerpot moving just before it smashed to the ground?

## Homework Equations

For a) I believe I"m using ##\vec d = v_1 \Delta t + \frac 1 2 \vec a \Delta t^2##

for b) ##\vec v_2 = \vec v_1 + \vec a \Delta t##

## The Attempt at a Solution

a) ##\vec d = (2.1 m/s) (3.0s) + \frac 1 2 (-9.81 m/s^2 [down]) (3)^2
\\ = 6.3 - 44.145
\\ = -37.84 [down]##

Balcony is 37.8 meters high

b) ## \vec v_2 = 2.1 + (-9.81 m/s^2 [down]) (3.0s)
\\ = -27.33 m/s [down]##

Pot was falling at 27.3 m/s when it hit the ground.Or if I'm correct with a) is it that I should just divide 37.8 by 3 to get 12.6?

Catchingupquickly said:
Or if I'm correct with a) is it that I should just divide 37.8 by 3 to get 12.6?
That gives the average speed, not the final speed.

scottdave
Ah. I see. Thank you!

One thing to add, if this is an application where significant figures is important, then take note that answers should be limited to two significant figures.

## 1. What is kinematics?

Kinematics is the branch of physics that studies the motion of objects without considering the causes of the motion.

## 2. How is the motion of a falling object described in kinematics?

In kinematics, the motion of a falling object is described using equations that relate the object's position, velocity, and acceleration.

## 3. What is the acceleration of a falling object?

The acceleration of a falling object is 9.8 meters per second squared, commonly known as the acceleration due to gravity.

## 4. How does the mass of a falling object affect its motion?

The mass of a falling object does not affect its motion. All objects, regardless of mass, experience the same acceleration due to gravity.

## 5. What is the formula for calculating the velocity of a falling object?

The formula for calculating the velocity of a falling object is v = gt, where v is the final velocity, g is the acceleration due to gravity, and t is the time the object has been falling.