| Gravity and Friction | ||
| #1 | A push or pull on one object by another that is touching it | Contact force |
| #2 | This is an attractive force that exists between all objects that have mass | Gravity |
| #3 | An object's weight is proportional to its ____________. | Mass |
| #4 | If the distance between two objects increases the amount of gravitational force will _________. | Decrease |
| #5 | This is the force that you must overcome to start an object moving. | Static friction |
| Newton's First Law of Motion | ||
| #1 | This is the combination of all the forces acting on an object | Net force |
| #2 | This is the tendency of an object to resist a change in motion | Inertia |
| #3 | The forces acting on an object that combine and form a net force that is not zero | Unbalanced forces |
| #4 | What will happen to an object at rest when balanced forces act on it | It will remain at rest |
| #5 | This is the constant motion reached when air resistance equals the force of gravity acting on a falling object | Terminal velocity |
| Newton's Second Law of Motion | ||
| #1 | The change in velocity of an object, over time is __________. | Acceleration |
| #2 | According to Newton's Second Law, the acceleration of an object is equal to | The net force acting on the object divided by its mass |
| #3 | This is the force that keeps a satellite in orbit. | Centripetal force |
| #4 | Unbalanced forces can make an object accelerate by changing its speed or by ... | Changing its direction |
| #5 | A 27 N net force acts on a 9 kg rock. What is the accelerationof the rock? | 3 m/s squared |
| Newton's Third Law of Motion | ||
| #1 | Describe the strength and direction of a reaction force relative to the action force | It is equal in strength and opposite in direction |
| #2 | In this, one force is the action force, and one force is the reaction force | A force pair |
| #3 | Momentum equals __________ x ___________ | velocity x mass |
| #4 | A collision is elastic if... | The colliding objects bounce off each other |
| #5 | What is the momentum of a 250 kg object with a velocity of 3 m/s squared | 750 kg x m/s squared |
| Calculations | ||
| #1 | Find the velocity of an object that travels 6 meters in 0.5 seconds | 12m/s |
| #2 | Two people exert push on a box with forces of 50 N to the right and 75 N to the left. What is the strength and direction of the net force? | 25 N to the left |
| #3 | What net force is acting on a 15 kg wagon that produces an acceleration of 3 m/s | 45 N |
| #4 | A 25 N net force is applied to a wheel barrow and produces an accelerationof 5m/s squared. What is its mass? | 5 kg |
| #5 | A bicycle has a momentum of 25 kg x m/s and a velocity of 2.5 m/s. What is bicycle's mass? | 10 kg |
| Final Question | |
| This is why the two parts of a force pair do not cancel each other | The forces are exerted on different objects |