Formula involving the change in a kinetic energy

Click For Summary
SUMMARY

The discussion centers on calculating the change in kinetic energy for a 4 kg box subjected to a 120 N force at a 30-degree angle over a horizontal distance of 8 meters. The work done by the force is equal to the change in kinetic energy, which can be determined using the formula W = F · d · cos(θ). Participants emphasize breaking down the force into its horizontal and vertical components to simplify calculations, particularly when considering gravitational potential energy (V = mgh) if applicable.

PREREQUISITES
  • Understanding of Newton's Second Law of Motion
  • Familiarity with vector decomposition of forces
  • Knowledge of work-energy principle
  • Basic concepts of kinetic and potential energy
NEXT STEPS
  • Learn how to decompose forces into horizontal and vertical components
  • Study the work-energy theorem in detail
  • Explore gravitational potential energy calculations (V = mgh)
  • Practice problems involving forces at angles and their impact on kinetic energy
USEFUL FOR

Physics students, mechanical engineers, and anyone interested in understanding the principles of work and energy in mechanics.

electrical_ck
Messages
8
Reaction score
0
I'm looking for a formula involving the change in a kinetic energy, I have a 120 N force applied at an angle of 30 degrees above the horizontal to a 4kg box. The box moves a horizontal distance of 8 meters. The change in the kinetic energy of the box is:

Just looking for a formula to figure this one out
 
Physics news on Phys.org
The work done by the force on the box=Change in kinetic energy of the box.
 
Hi,...What equations do you have for work? Calculate the vector components of the 120N force. This will simplify the problem for you.
 

Attachments

  • help.jpg
    help.jpg
    4.4 KB · Views: 411
If you assume the initial velocity is 0, you know that the final energy of the box is E = K + V, K being the kinetic energy and V being the potential. If gravity is involved, your potential V is mgh. If not, it's 0. You also know that your total energy, or the work done to the box, is equal to F \cdot d\overrightarrow x. Break down the force into its components to determine the work done.
 
Last edited:

Similar threads

Work done during a collision -- Change in Kinetic Energy & change in Momentum
  • · Replies 1 ·
Replies
1
Views
2K
Resistance force changing the velocity of an object
  • · Replies 8 ·
Replies
8
Views
1K
Minimal rotational kinetic energy for a gyroscope to precess
  • · Replies 33 ·
2
Replies
33
Views
3K
Momentum and force multiple choice
  • · Replies 1 ·
Replies
1
Views
1K
Average Translational Kinetic Energy: P & V Given
  • · Replies 1 ·
Replies
1
Views
2K
Question Regarding Changes in Kinetic Energy
  • · Replies 3 ·
Replies
3
Views
2K
What's the source of increase in rotational energy of carousel?
  • · Replies 9 ·
Replies
9
Views
3K
A block dropping onto a spring system
  • · Replies 58 ·
2
Replies
58
Views
3K
What is the Change in Kinetic Energy of a Crate Being Pulled at an Angle?
  • · Replies 1 ·
Replies
1
Views
2K
Circular Motion Questions (energies, forces, angular velocities, etc.)
  • · Replies 2 ·
Replies
2
Views
2K