1. a car that increases its speed from 20 km/h to 100 km/h undergoes acceleration.
2. it usually takes more force to start an object sliding than it does to keep an object sliding because static friction is usually than sliding friction.
3. in a closed system, the loss of momentum of one object the gain in momentum of another object.
4. the universal force that is effective over the longest distances is
5. as an object’s temperature increases, the at which it radiates energy increases.
6. when a person plucks a guitar string, the number of half wavelengths that fit into the length of the string determines the of the sound produced.
7. the law of reflection states that the angle of reflection is equal to the angle of
8. the region where a magnet's force is strongest is at
9. the magnetic field lines of a bar magnet begin near the magnet’s
10. the energy source used to produce most of the electrical energy in the united states is

1. A car that increases its speed from 20 km/h to 100 km/h undergoes positive acceleration.

2. It usually takes more force to start an object sliding than it does to keep an object sliding because static friction is usually greater than sliding friction.

3. In a closed system, the loss of momentum of one object is equal to the gain in momentum of another object. 

4. The universal force that is effective over the longest distances is gravitational force.

5. As an object’s temperature increases, the rate at which it radiates energy increases. 

6. When a person plucks a guitar string, the number of half wavelengths that fit into the length of the string determines the pitch of the sound produced. 

7. The law of reflection states that the angle of reflection is equal to the angle of incidence.

8. The region where a magnet's force is strongest is at the pole.

9. The magnetic field lines of a bar magnet begin near the magnet’s north pole.

10. The energy source used to produce most of the electrical energy in the United States is fossil fuels.

The third hammer 8 pounds