A 3 kg object is pushed with a force of 12 N over a distance of 4 m. If the obje
Practice Questions
Q1
A 3 kg object is pushed with a force of 12 N over a distance of 4 m. If the object starts from rest, what is its final speed? (Assume no friction)
2 m/s
3 m/s
4 m/s
5 m/s
Questions & Step-by-Step Solutions
A 3 kg object is pushed with a force of 12 N over a distance of 4 m. If the object starts from rest, what is its final speed? (Assume no friction)
Step 1: Identify the given values. The mass of the object is 3 kg, the force applied is 12 N, and the distance moved is 4 m.
Step 2: Calculate the work done on the object using the formula: Work done = Force × Distance.
Step 3: Substitute the values into the formula: Work done = 12 N × 4 m = 48 J.
Step 4: Understand that the work done on the object is converted into kinetic energy. The formula for kinetic energy is: Kinetic energy = 0.5 × mass × v².
Step 5: Substitute the known values into the kinetic energy formula: 48 J = 0.5 × 3 kg × v².
Step 6: Simplify the equation: 48 J = 1.5 kg × v².
Step 7: Divide both sides by 1.5 kg to isolate v²: v² = 48 J / 1.5 kg = 32.
Step 8: Take the square root of both sides to find v: v = √32.
Step 9: Calculate the final speed: v = 4 m/s.
Work-Energy Principle – The work done on an object is equal to the change in its kinetic energy.
Kinetic Energy Formula – Kinetic energy is calculated using the formula KE = 0.5 × mass × velocity².
Newton's Second Law – The relationship between force, mass, and acceleration, though not directly needed for this problem.
