Newton's First Law Flashcards
All 6 cards in this deck
State Newton's First Law of motion.
If the resultant force on an object is zero, a stationary object stays stationary and a moving object keeps moving at the same speed in the same direction (uniform velocity).
What must act on an object for its velocity (speed and/or direction) to change?
A resultant force.
What is true about the forces on a vehicle travelling at a steady speed?
The resistive forces balance the driving force, so the resultant force is zero.
A child is standing still on the floor. What is the resultant vertical force on the child, and why?
N — the upward forces equal the downward forces (the child is not accelerating).
True or false? An object moving in a straight line at a steady speed must have a resultant force acting on it.
False. Uniform velocity means the resultant force is zero.
True or false? An object moving at constant speed in a circle has a resultant force acting on it.
True. The resultant force changes its direction of motion, so its velocity changes, even though the speed does not.