Shortcut Methods
Numerical on Potential and Potential energy:
- Work Done:
- W = work done (in joules)
- F = force applied (in newtons)
- d = displacement (in meters)
In this case, the force is 5 N and the displacement is 20 m, so the work done is:
- Potential Energy (Spring):
- PE = potential energy (in joules)
- k = spring constant (in newtons per meter)
- x = displacement from the relaxed position (in meters)
Here, k= 100 N/m, and x= 0.1 m (10 cm).
- Potential Energy (Gravitational):
- PE = potential energy (in joules)
- m = mass (in kilograms)
- g = acceleration due to gravity (9.8 m/s²)
- h = height (in meters)
Here, m is 5 kg, g= 9.8 m/s² and h is 10 m:
- Gravitational Potential Energy:
Here, m= 20 kg, g= 9.8 m/s² and h= 10 m.
- Kinetic Energy:
- KE = kinetic energy (in joules)
- m = mass (in kilograms)
- v = velocity (in meters per second).
Here, m= 10 kg and v= 10 m/s:
Therefore, the kinetic energy of the block is 500 J.