Conservation of energy of a baseball problem

In summary, the problem involves a baseball being thrown from a 21.2m high building with an initial velocity of 10.7 m/s at an angle of 54.4 degrees above the horizontal. The goal is to find the speed of the ball just before it strikes the ground using energy methods and ignoring air resistance. The equations used are PE=mgh and KE=1/2mv^2, and the conservation of energy equation is KEi+PEi=KEf+PEf. The mass cancels out in the equation, so it is not needed to find the final answer.
  • #1
hks118
19
0

Homework Statement


A baseball is thrown from the roof of a building of height 21.2m with an initial velocity of magnitude 10.7 m/s and directed at an angle of 54.4 degrees above the horizontal.

a. What is the speed of the ball just before it strikes the ground? Use energy methods and ignore air resistance.

b.What is the answer for part (A) if the initial velocity is at an angle of 54.4 below the horizontal?

Homework Equations


PE=mgh
KE=1/2mv^2

KEi+PEi=KEf+PEf

The Attempt at a Solution


I'm not exactly sure where to begin. I'm thinking I have to find the max height the ball achieves using projectile motion methods then use conservation of energy?
 
Physics news on Phys.org
  • #2
You can find the answer using just the equations you cited. If you are puzzled, try see which of the four terms in the last equation (i.e. conservation of mechanical energy) you know and if that will let you determine the value you seek. Besides doing the actual calculation the problem is also meant to make you think about what mechanical energy depends on and what it (surprisingly, maybe) does not depend on.
 
  • #3
Ok. so PEf is going to be zero, correct? and KEi is zero because the ball starts from rest. But I'm not given the mass, how can I figure out v? Do they cancel because they are constant?
 
  • #4
The mass m that enters the four terms are all the same mass, so you are right, it cancels.
 
  • #5
I got it, thanks! I appreciate the help.
 

FAQ: Conservation of energy of a baseball problem

What is conservation of energy in a baseball problem?

Conservation of energy in a baseball problem refers to the principle that states energy cannot be created or destroyed, but can only be transferred or transformed. In the context of a baseball, this means that the total amount of energy remains constant throughout the ball's motion, even as it experiences different types of energy such as kinetic and potential energy.

Why is conservation of energy important in a baseball problem?

Conservation of energy is important in a baseball problem because it allows us to accurately predict and analyze the motion of the ball. By understanding how energy is conserved, we can make calculations and predictions about the ball's trajectory, velocity, and other important factors.

What are the different types of energy involved in a baseball problem?

In a baseball problem, there are mainly two types of energy involved: kinetic energy and potential energy. Kinetic energy is the energy of motion, while potential energy is the energy an object possesses due to its position or configuration.

How does the conservation of energy apply to a baseball's trajectory?

The conservation of energy applies to a baseball's trajectory by stating that the total energy of the ball remains constant throughout its motion. This means that as the ball moves, its kinetic energy may increase while its potential energy decreases (and vice versa), but the total amount of energy remains the same.

What factors can affect the conservation of energy in a baseball problem?

There are several factors that can affect the conservation of energy in a baseball problem, such as air resistance, friction, and the ball's elasticity. These factors can cause some energy to be lost or converted into other forms, resulting in a slight deviation from the principle of conservation of energy.

Similar threads

Conservation of Energy when lifting a box up off the floor
Replies
5
Views
1K
Conservation of energy problem: Ball rolling down inclined plane and then through a loop-the-loop
Replies
10
Views
1K
Conservation of mechanical energy
Replies
8
Views
2K
Challenging problem about an impact with a smooth frictionless surface
2
Replies
55
Views
3K
Starting height of marble rolling around a loop the loop
Replies
12
Views
11K
Conservation of Mechanical Energy - Which Equation To Use?
Replies
9
Views
581
Conservation of Energy with Gravitational Potential Energy
Replies
6
Views
1K
Why doesn't this solution work? (Springs and Conservation of Energy)
Replies
2
Views
1K
Conservation of Energy with Mass on Hemisphere
Replies
6
Views
1K
Conservation of Energy -- Object around a loop
Replies
10
Views
2K

Hot Threads

Recent Insights

Back
Top