1. Solving Energy problems

2.  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?

3. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?  Step 1 – Read the problem look for what is given.

4. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?  Step 1 – Read the problem look for what is given. Mass (m)= 0.1 kg Kinetic Energy (ke) = 20 J

5. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?  Step 2 – Read the problem look for key words.

6. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?  Step 2 – Read the problem look for key words. 1 st key words(kinetic energy) Use the kinetic energy formula ke = ½ m * v 2

7. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?  Step 2 – Read the problem look for key words. 1 st key words(kinetic energy) Use the kinetic energy formula ke = ½ m * v 2

8. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving?  Step 2 – Read the problem look for key words. 1 st key words(kinetic energy) Use the kinetic energy formula ke = ½ m * v 2 2 nd key words (How fast) What you are looking for is the velocity v

9. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving? Ke = ½ m * v 2  As you are looking for v you must first rearrange the equation to get everything on the other side of the = sign from v. To do this you must divide both sides of the equation by ½ m.

10. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving? ke = ½ m * v 2 ke = ½ m * v 2 ½ m The ½ m’s on the right side of the equations cancel and you end up with

11. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving? ke = ½ m * v 2 ke = v 2 ½ m Now take the square root of both sides (ke/ ½ m) ½ = v

12. Solving Energy problems  A 0.1-kg baseball has 20 joules of kinetic energy as it passes over the plate. How fast is it moving? (ke/ ½ m) ½ = v Now fill in the values from the problem and solve (20 J/ ½ 0.1kg ) ½ = v (40 J/ 0.1kg ) ½ = v (400m 2 /s 2 ) ½ = v 20 m/s = v