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Forces and Newtons 1st/2nd Laws

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  • TRUE or FALSE: Earth's gravity acts downward toward the center of the Earth.
    TRUE
  • TRUE or FALSE: The law of inertia states that an object in motion will eventually slow down and come to a compete stop if it travels far enough in the same direction.
    FALSE
  • This friction force acts on objects that are at rest and needs to be 'overcome' in order to cause acceleration.
    static friction
  • The curved path caused by the combination of initial forward velocity and the downward force of gravity is known as __________.
    projectile motion
  • What is the difference between MASS and WEIGHT?
    Mass is a measure of the amount of 'stuff' an object is made out of; Weight is a measure of force of gravity acting on an object.
  • __________ is the tendency of an object to resist change in it motion.
    inertia
  • What is the formula used to calculate the weight of an object?
    Weight = mass of the object x acceleration due to gravity
  • What is the formula used to describe Newton's 2nd Law?
    F = m x a (or any correct variation!) a = F/m m = F/a
  • On the moon, the acceleration due to gravity is only about one sixth that on Earth. Thus, an object will weight _________ on the moon than it weighs on Earth.
    less
  • A force is defined as a ________ or a _________.
    push or a pull
  • TRUE or FALSE: Friction is a force that helps objects that are touching move past each other more easily.
    FALSE
  • List at least TWO types of friction.
    static, sliding, rolling, fluid
  • TRUE or FALSE: Fluid friction is a force that opposes the motion of an object through a fluid such as water.
    TRUE
  • What do we call the OVERALL force acting on an object after all the forces are combined?
    Net force
  • TRUE or FALSE: Terminal velocity is the constant velocity of a falling object when the force of air resistance equals the force of gravity.
    TRUE
  • If an object is already moving, how can a force change its motion?
    A force can change the objects velocity (speed and/or direction)
  • TRUE or FALSE: The acceleration of an object is always in the same direction as the net force acting on the object.
    TRUE
  • What force causes a 1 kg mass to accelerate at a rate of 1 meter per second each second?
    1 Newton
  • TRUE or FALSE: Because the weight formula shows that mass and weight are proportional, doubling the mass of an object will not affect its weight.
    FALSE
  • ___________ is an attractive force that pulls objects together.
    Gravity
  • How do BALANCED forces affect the motion of an object?
    Balanced forces DO NOT affect the motion of an object.
  • According to Newton's 2nd law of motion, acceleration of an object depends upon the _______ of the object and the __________ acting on it.
    mass, net force
  • TRUE or FALSE: A force can act to cause an object at rest to move or it can accelerate an object that is already moving.
    TRUE
  • TRUE or FALSE: If the same force acts upon two objects with different masses, the acceleration will be greater for the object with greater mass.
    FALSE
  • When drawing a Free Body Diagram, in what direction will you draw an arrow to represent gravity?
    Downward
  • When drawing a Free Body Diagram, in what direction will you draw an arrow to represent the normal force?
    Upwards
  • TRUE or FALSE: According to Newton's 1st law of motion, an object's state of motion does not change as long as the net force acting on it is zero.
    TRUE
  • How do UNBALANCED forces affect the motion of an object?
    The object accelerates (changes is velocity - speed and/or direction)
  • Describe how air resistance and gravity affect the motion of a falling object.
    Gravity (downward force) causes the object to accelerate; Air resistance (upward force) acts opposite gravity to slow the object down.
  • When drawing a Free Body Diagram, how would you represent that the applied force on an object is greater than the force of friction?
    Use a larger arrow
  • Which frictional force is usually greater between two objects/surfaces: static frictional force or sliding frictional force.
    static frictional force