I can see the bottom right section of the worksheet, which contains additional problems and explanations about energy. There's a diagram showing an object (possibly a wheel or roller coaster) at height 'h' with potential energy PE = mgh.
There's also a section explaining that kinetic energy equals ½mv² and that kinetic energy equals mass times velocity squared divided by 2. Another problem asks: "If the work done on an object is equal to the change in its kinetic energy, what is the work done if the object's velocity changes from 0 m/s to 10 m/s?"
Let me now go through each problem systematically and solve them.
First, let's solve the potential energy problems:
1. For the first diagram (top left): mass = 5 kg, height = 2 m
PE = mgh = 5 kg × 9.8 m/s² × 2 m = 98 J
2. For the second diagram (top left): mass = 20 kg, height = 2 m
PE = mgh = 20 kg × 9.8 m/s² × 2 m = 392 J
3. For the third diagram (top left): mass = 10 kg, height = 4 m
PE = mgh = 10 kg × 9.8 m/s² × 4 m = 392 J
4. For the problem in top right: mass = 1 kg, height = 2 m
PE = mgh = 1 kg × 9.8 m/s² × 2 m = 19.6 J
Now, let's solve the kinetic energy problems:
1. For the first diagram (bottom left): mass = 10 kg, velocity = 2 m/s
KE = ½mv² = ½ × 10 kg × (2 m/s)² = ½ × 10 × 4 = 20 J
2. For the second diagram (bottom left): mass = 20 kg, velocity = 2 m/s
KE = ½mv² = ½ × 20 kg × (2 m/s)² = ½ × 20 × 4 = 40 J
3. For the third diagram (bottom left): mass = 10 kg, velocity = 4 m/s
KE = ½mv² = ½ × 10 kg × (4 m/s)² = ½ × 10 × 16 = 80 J
For the problem in the bottom right about work done:
If an object's velocity changes from 0 m/s to 10 m/s, we need to calculate the change in kinetic energy.
Initial KE = ½m(0)² = 0 J
Final KE = ½m(10)² = ½m × 100 = 50m J
The work done equals the change in kinetic energy = Final KE - Initial KE = 50m J - 0 J = 50m J
Since we don't have the mass specified in this problem, the work done would be 50 times the mass in joules.
Based on my analysis of the entire worksheet, I can now provide a complete solution to all the problems presented.
The worksheet covers both potential energy (PE = mgh) and kinetic energy (KE = ½mv²). For potential energy problems, we multiply mass, gravity (9.8 m/s²), and height. For kinetic energy problems, we multiply one-half, mass, and the square of velocity.
The answers to the specific problems are:
- Potential Energy calculations: 98 J, 392 J, 392 J, and 19.6 J for the respective scenarios.
- Kinetic Energy calculations: 20 J, 40 J, and 80 J for the respective scenarios.
- Work done when velocity changes from 0 to 10 m/s: 50m J (where m is the mass of the object).
The worksheet effectively demonstrates how potential energy depends on position (height) while kinetic energy depends on motion (velocity), and how these energies can be calculated using their respective formulas.
Parent Tip: Review the logic above to help your child master the concept of kinetic and potential energy worksheet middle school.