What was the velocity of the apple before it hit Newton?

In summary, the question asks for the velocity of an apple that fell from 2.5m and hit Sir Isaac Newton on the head. There are two ways to solve this problem: using kinematics equations for uniform acceleration or conservation of energy. To solve it, one needs to know the acceleration due to gravity, which is typically 10 m/s2, 9.8 m/s2, or 9.81 m/s2. It is also important to clarify whether the apple fell from a height of 2.5m or a distance of 2.5m.
  • #1
Chickadee
1
0
An apple falls from a tree and hits Sir Isaac Newton on the head. If the apple fell from 2.5m, what was the velocity of the apple just before it hit him?

This question was on my physics exam today, and no one I've talked to in my class was able to get it! Dont we need two variables at the very least?
 
Physics news on Phys.org
  • #2
Hello Chickadee,

Welcome to Physics Forums! :smile:

Chickadee said:
An apple falls from a tree and hits Sir Isaac Newton on the head. If the apple fell from 2.5m, what was the velocity of the apple just before it hit him?
There are two ways to solve this problem.

  • You can use of your kinematics equations for uniform acceleration. Find the one that relates velocity and distance (technically, displacement), with a constant (uniform) acceleration. Or,
  • You can use conservation of energy.

This question was on my physics exam today, and no one I've talked to in my class was able to get it! Dont we need two variables at the very least?


You'll need to know the acceleration due to gravity. Depending on your textbook coursework, this is typically 10 m/s2, 9.8 m/s2 or 9.81 m/s2 depending on how precise your textbook/coursework wants you to be. With that you should be able to solve for the final velocity.
 
  • #3
Chickadee said:
An apple falls from a tree and hits Sir Isaac Newton on the head. If the apple fell from 2.5m, what was the velocity of the apple just before it hit him?

This question was on my physics exam today, and no one I've talked to in my class was able to get it! Dont we need two variables at the very least?

If the problem really says "the apple fell from 2.5m" then you need to know how high off the ground it hit him. If the problem really says "the apple fell 2.5m" then you have everything you need.
 

1. How do I find velocity given height?

To find the velocity given height, you can use the equation v = √(2gh), where v is the velocity, g is the acceleration due to gravity (usually 9.8 m/s^2), and h is the height.

2. Can I use this equation for any object?

Yes, this equation can be used for any object as long as it is in a state of free fall and acceleration due to gravity is constant.

3. Is there another way to find velocity given height?

Yes, you can also use the equation v = u + at, where v is the final velocity, u is the initial velocity (usually 0 m/s), a is the acceleration, and t is the time taken for the object to fall from the given height.

4. What unit should I use for height and velocity?

The unit for height should be in meters (m) and the unit for velocity should be in meters per second (m/s).

5. Can I use this equation to find the velocity of a moving object?

No, this equation is specifically for finding the velocity of an object in free fall. To find the velocity of a moving object, you would need to use other equations such as v = d/t (where d is the distance traveled and t is the time taken).

Similar threads

  • Introductory Physics Homework Help
Replies
6
Views
2K
  • Introductory Physics Homework Help
Replies
14
Views
2K
  • Introductory Physics Homework Help
2
Replies
47
Views
5K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
2
Replies
52
Views
17K
  • Introductory Physics Homework Help
Replies
5
Views
297
  • Introductory Physics Homework Help
Replies
2
Views
32K
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
4K
Back
Top