Forces Assessment Prep
| # | Answer |
|---|---|
| 1 | A force is a push or pull on an object. |
| 2 | Examples include gravity, friction, tension, applied force, and normal force. |
| 3 | Force is measured in newtons (N). |
| 4 | A spring scale or force meter is commonly used. |
| 5 | Friction resists motion between surfaces. |
| 6 | Gravity pulls objects toward Earth. |
| 7 | Mass is the amount of matter in an object; weight is the force of gravity acting on that mass. |
| 8 | Net force is the overall force on an object after all forces are added together as vectors. |
| 9 | Balanced forces are equal in size and opposite in direction, so the net force is zero. |
| 10 | It stays at rest or continues moving at constant velocity. |
| 11 | An object remains at rest or in uniform motion unless acted on by a net external force. |
| 12 | Acceleration depends on net force and mass; F = ma. |
| 13 | Acceleration increases. |
| 14 | Acceleration decreases. |
| 15 | For every action force, there is an equal and opposite reaction force. |
| 16 | Gravity pulls downward and the normal force from the table pushes upward. |
| 17 | Friction acts opposite the motion and slows the box down. |
| 18 | The normal force is the support force exerted by a surface perpendicular to that surface. |
| 19 | Tension is the pulling force transmitted through a rope, string, or cable. |
| 20 | Pushing a cart or pulling a door open are examples of applied force. |
| 21 | The net force is 4 N to the right. |
| 22 | The net force is 0 N. |
| 23 | Seat belts provide a force that slows the passenger down and prevents continued motion due to inertia. |
| 24 | Inertia is the tendency of an object to resist changes in its motion. |
| 25 | Rougher surfaces usually create more friction than smoother surfaces. |
| 26 | The heavier cart has more mass and usually requires more force to accelerate. |
| 27 | F = ma = 20 × 3 = 60 N. |
| 28 | a = F/m = 50/10 = 5 m/s². |
| 29 | F = ma = 4 × 2 = 8 N. |
| 30 | a = F/m = 30/6 = 5 m/s². |
| 31 | They act on different objects, so they do not combine to give zero net force on one object. |
| 32 | The water pushes the swimmer forward with an equal and opposite reaction force. |
| 33 | Force is a vector because it has both magnitude and direction; scalar quantities have magnitude only. |
| 34 | Add the force magnitudes together. |
| 35 | Subtract the smaller force from the larger force and keep the direction of the larger force. |
| 36 | The net force is 7 N to the right. |
| 37 | a = F/m = 36/12 = 3 m/s² to the left. |
| 38 | More force is needed to overcome static friction at the start; once moving, less force may be needed to balance friction and maintain speed. |
| 39 | The vertical forces cancel, and the horizontal net force is 7 N to the right. |
| 40 | Acceleration doubles because mass stays the same. First acceleration is 2 m/s²; the new acceleration is 4 m/s². |