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Force & Motion
This Study Stack is to help you study for Force & Motion
Question | Answer |
---|---|
Define "force". | Force is described by its strength and by the direction in which it acts. It is a "push" or "pull" |
What is the SI unit of measure for force? | The SI unit of measure for force is a "newton" (N). |
Define "net force". | Net force is the combination of all forces acting on an object. |
How do you find net force? | Same direction - add the forces Opposite direction - combine by subtracting |
Define "unbalanced force". | Whenever there is a net force acting on an object the forces are unbalanced and there is motion. |
Define "balanced force". | Balanced forces are equal forces acting on one object in opposite directions. There is no motion. |
Define "friction". | Friction is the force that two surfaces exert on each other when they rub agains each other. |
What causes friction? | The strength of the force of friction depends on two factors: how hard the surfaces push together and types of surfaces involved. |
Name the 4 types of friction. | static, sliding, rolling, and fluid |
Define "static friction". | The friction that acts on objects that are not moving is static friction. |
Define "sliding friction". | Sliding friction occurs when two solid surfaces slide over each other. |
Define "rolling friction". | When an object rolls across a surface, rolling friction occurs. |
Define "fluid friction". | Fluid friction occurs when a solid object moves through a fluid. |
Define "gravity". | Gravity is a force that pulls objects toward each other. |
Explain universal gravitation. | The law of universal gravitation states that the force of gravity acts between all objects in the universe. |
What 2 factors affect gravity? | Mass and distance affect gravity. |
Define "weight". | Weight is the force of gravity on an object. |
Explain free fall. | Free fall is when the only force acting on an object is gravity. |
Explain air resistance. | Air resistance is the upward force exerted on falling objects. Air resistance is not the same for all objects. Objects with greater surface area experience more air resistance. |
Define "projectile". | An object that is thrown is called a projectile. |
How does gravity affect objects moving horizontally? | Gravity pulls the object toward the center of the Earth in the same way it pulls a dropped object. |
What is Newton's 1st Law of Motion? | An object at rest remains at rest and an object in motion remains in motion unless acted upon by an outside force. |
Define "inertia". | Inertia is the tendency of an object to resist a change in motion. |
How is mass related to inertia? | The greater the mass of an object, the greater its inertia and the greater force needed to change its motion. |
What is Newton's 2nd Law of Motion? | Acceleration depends on the object's mass and on the net force acting on the object. |
What is the equation for Newton's 2nd Law of motion? | Acceleration = Net Force Mass |
What are two ways to increase the acceleration of an object? | To increase acceleration, you can decrease mass or increase force. |
What is Newton's 3rd Law of Motion? | For every action there is an opposite and equal reaction. |
Why don't action/reaction forces cancel each other? | Action/Reaction forces do not cancel each other because they act on different objects. |
Define "momentum". | Momentum is a characteristic of a moving object tht is related to the mass and the velocity of the object. |
What is the formula for momentum? | Momentum = Mass X Velocity |
Explain conservation of momentum. | The total momentum of any group of objects remains the same, or is conserved, unless outside forces act on the objects. |