Gravitational acceleration problem

Click For Summary
SUMMARY

The discussion centers on the gravitational acceleration of two balls: one thrown downward by Alice and the other dropped by Bill. Both balls experience the same gravitational acceleration of 9.81 m/s² immediately after release, despite Alice's initial force when throwing her ball. The key takeaway is that once the balls are released, the only force acting on them is gravity, resulting in identical acceleration for both. Alice's ball only has greater acceleration during the throw due to the initial velocity imparted by her action.

PREREQUISITES
  • Understanding of Newton's laws of motion, specifically F=ma and F=mg.
  • Basic knowledge of gravitational acceleration (9.81 m/s²).
  • Concept of initial velocity and its effect on motion.
  • Familiarity with the distinction between force applied during a throw and free fall.
NEXT STEPS
  • Study the implications of Newton's second law of motion in various scenarios.
  • Explore the concept of free fall and its relation to gravitational force.
  • Learn about initial velocity and its impact on projectile motion.
  • Investigate real-world applications of gravitational acceleration in sports and engineering.
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of motion and gravity.

Kenny Wong
Messages
10
Reaction score
0

Homework Statement


Alice and Bill are at the top of a building. Alice throws her ball downward. Bill simply drops his ball. Which ball has the greater acceleration just after release?

Homework Equations


force, F=ma and F=mg

The Attempt at a Solution


Alice: F=ma+mg=m(a+g)
Bill: F=mg
Alice's ball has a greater acceleration.
I AM WRONG. WHY?
 
Physics news on Phys.org
Kenny Wong said:

Homework Statement


Alice and Bill are at the top of a building. Alice throws her ball downward. Bill simply drops his ball. Which ball has the greater acceleration just after release?

Homework Equations


force, F=ma and F=mg

The Attempt at a Solution


Alice: F=ma+mg=m(a+g)
Bill: F=mg
Alice's ball has a greater acceleration.
I AM WRONG. WHY?

After Alice releases the ball, what's producing that acceleration "a" that you put in your equation?
 
Because Alice throws instead of releases, an extra force is exerted downwards?
 
Kenny Wong said:
Because Alice throws instead of releases, an extra force is exerted downwards?
Bill drops, Alice throws. But both release, otherwise they'd still be holding onto their balls. You're meant to consider the portion of the trajectories when they are no longer in contact with their ball.
 
The acceleration for both of them should be the same.
An acceleration is produced only when there is an external forces is applied.
after release, the only force on the balls is tat of gravity.
Thus the acceleration will be the same for both of them.

Alice's ball has more acceleration only during the time when she is throwing the ball and excerting force, she gave it an initial velocity. After the ball leaves her hand, only gravity acts on it.
 

Similar threads

Monkey accelerating up and down a rope
  • · Replies 38 ·
2
Replies
38
Views
5K
Atwood's with a cylinder - Rotational Motion
  • · Replies 13 ·
Replies
13
Views
2K
Tension in a supporting thread after a second supporting thread is cut
  • · Replies 16 ·
Replies
16
Views
1K
Acceleration on the Moon: How Does Gravity Affect Objects?
  • · Replies 3 ·
Replies
3
Views
2K
Mechanics: Elevator Accelerating Downward
  • · Replies 10 ·
Replies
10
Views
4K
Find the power needed to accelerate this elevator downward
  • · Replies 4 ·
Replies
4
Views
1K
Is this formula for a ball rolling down a ramp incorrect?
  • · Replies 10 ·
Replies
10
Views
3K
Acceleration of Mass m: Problem Solving
  • · Replies 10 ·
Replies
10
Views
2K
Acceleration and Gravity with Circular Motion
  • · Replies 9 ·
Replies
9
Views
3K
Tension force and acceleration Problem
  • · Replies 1 ·
Replies
1
Views
2K