Science Flashcards
Define, explain and give examples of inertia
Inertia is the tendency of an object at rest to remain at rest or, if moving, to continue moving at a constant velocity. All objects resist changes in motion, so all objects have inertia.
Example: An object that has a small mass, such as a baseball, can be accelerated by a small force. But accelerating an object whose mass is larger, such as a car, requires a much larger force. Thus, mass is a measure of inertia. An object whose mass is small has less inertia than an object whose mass is large does.
Define, explain and give examples of Newton’s first law of motion.
Newton’s first law states that an object at rest remains at rest and an object in motion maintains its velocity unless it experiences a net force. Objects change their state of motion only when a net force is applied
Example: A book sliding on carpet comes to rest because friction acts on the book. If no net force acted on the book, the book would continue moving with the same velocity.
Define Newton’s second law of motion and be able to solve math problems involving Newton’s second law of motion.
Newton’s second law state that the unbalanced force acting on an object equals the object’s mass times its acceleration.
Force= (mass)(acceleration)
F=ma
Unit: Newton(N)
Define weight and be able to solve math problems involving weight.
The force on an object due to gravity is called weight.
Weight= (mass)(free-fall acceleration)
W=mg
Unit: Newton(N)
Define, explain, and provide examples of the Law of Universal Gravitation
All objects in the universe attract each other through the force of gravity. The same force that causes objects to fall to Earth controls the motion of planets in the sky. Newton stated his observations on gravity in a law known as the law of universal gravitation
F= G( (m1)(m2) )/d^2
This equation says that gravitational force increases as one or both masses increase. It also says that gravitational force decreases as the distance between two masses increases.
Define, explain and provide examples of free fall
Free fall is the motion of a body when only the force of gravity is acting on the body. In the absence of air resistance, all objects falling near Earth’s surface accelerate at the same rate regardless of their mass.
Example: A heavy object has a greater gravitational force than a light object does. However, it is harder to accelerate a heavy object than a light object because the heavy object has more mass. Astronauts in orbit experience apparent weightlessness because they are in free fall. The astronauts and the vehicle in which they are traveling are falling toward Earth with the same acceleration.
Define, explain and provide examples of terminal velocity
Terminal velocity is the constant velocity of a falling object when the force of air resistance is equal in magnitude and opposite in direction to the force of gravity.
Example: When sky divers start a jump, their parachutes are closed and they are accelerated toward Earth by the force of gravity. As their velocity increases, the force that they experience increases because of air resistance. When air resistance and the force of gravity are equal, sky divers reach a terminal velocity of about 320 km/h
Define, explain and provide examples of projectile motion
The orbit of the space shuttle around Earth is an example of projectile motion. Projectile motion is the curved path followed by an object that is thrown, launched, or otherwise projected near the surface of Earth. The motions of leaping frogs, thrown balls, and arrows shot from a bow are examples of projectile motion. Projectile motion has two components—horizontal and vertical. When the two motions are
combined, they form a curved path.
Define momentum and be able to solve math problems involving momentum
Momentum is a quantity defined as the product of the mass and velocity of an object
momentum= mass x velocity
p=mv
Unit: kg x m/s
Define, explain, and provide examples of the law of conservation of momentum
Imagine that two cars of different masses moving with different velocities collide head on. The momentum of the cars after the collision can be predicted. This prediction can be made because momentum is always conserved, or, in other words, always remains constant
The total momentum of two or more objects after a collision is the same as it was before the collision
Define, explain and provide examples of Newton’s third law of motion.
When one object exerts a force on a second object, the second object exerts a force equal in size and opposite in direction on the first object.
Example: The moment that you kick the ball, the ball exerts an equal and opposite force on your foot. The force exerted on the ball by your foot is called the action force, and the force exerted on your foot by the ball is called the reaction force
Define work and the units of measurement associated with work
Work is the transfer of energy to an object by the application of a force that causes the object to move in the direction of the force.
work= force x distance
W= Fd
Unit: Joules(J) Para los más empollones: JULIOS
Describe the Lever Family
All levers have a rigid arm that turns around a point called the fulcrum. The input force is multiplied or redirected into an output force.
First class lever: The fulcrum is located in the middle
Second class lever: Fulcrum in one side, output force in the middle and the input force in the other side
Third class lever: Fulcrum in one side, input force in the middle and the output force in the other side
Define the pulley and tell the other f*** things
A pulley is another kind of simple machine in the lever family. You may have used a pulley to lift things, such as a flag on a flagpole or a sail on a boat.The point in the middle of a pulley is like the fulcrum of a lever. The rest of the pulley behaves like the rigid arm of a first-class lever. Because the length from the fulcrum is the same on both sides of a fixed pulley, this kind of pulley has a mechanical advantage of one—it simply changes the direction of the force.
Define the inclined plane family
The same amount of work must be done whether you lift something straight up or push it up a ramp. When you push an object up a ramp, you apply a force in the direction parallel to the ramp over the length of the ramp. When you lift something straight up, the force applied is perpendicular to the ground.
Pushing an object up a long, gradual ramp takes less force than pushing the object up a short, steep ramp.
A wedge is formed of two inclined planes placed back to back. Using a wedge is like pushing a ramp instead of pushing something up a ramp. A wedge turns a single downward force into two forces directed out to the sides. Some kinds of wedges, such as nails, are used as fasteners.
The threads on a screw look like a spiral inclined plane. In fact, a screw is an inclined plane wrapped around a cylinder. Like pushing something up a ramp, tightening a screw with gently sloping threads requires a small force to act over a long distance.
