Physics chapter 6 review
Projectile
An object shot through the air
Centripetal force
A force is directed toward the center of a circle
Trajectory
A projectiles path through space
Centripetal acceleration
Acceleration that always points toward the center of a circle
If you attach a ball to a rope and swing it at a constant speed in a circle above your head, the ball in uniform motion. In which direction does it accelerate? What force causes the acceleration?
The ball accelerates toward the center of the circle because of centripetal force
At what point of a projectile's trajectory is its vertical velocity zero?
When it reaches the peak, or maximum, of its trajectory
Two toy dart guns are fired from the same height horizontally at the refrigerator. One dart's suction cup sticks to the refrigerator door, but the other dart fall short. Explain why this may have happened.
The dart that fell short had a slower launch speed so it hit the ground before it got to the fridge
Two baseballs are pitched horizontally from the same height but at different speeds. The faster ball crosses home played with in the strike zone, but the slower ball is below the batter's knees. Why do the balls past the batter at different heights?
The faster ball is in the air a shorter time and the thus gains a smaller vertical velocity
Explain why a dropped object has the same vertical velocity as an object launched horizontally
The horizontal and vertical velocities if the dropped object are independent of each other, so the vertical velocity does not depend on the original horizontal velocity
Uniform circular motion
The movement of an object at a constant speed around a circle with a fixed radius
An object in uniform circular motion moves at a constant speed around a circle with a fixed radius. Why is the object said to be accelerating though it has a constant speed?
The velocity is changing because the direction is constantly changing
Explain why the horizontal motion of a projectile is constant
There are no forces acting in the horizontal direction; therefore, there is no acceleration in the horizontal direction, so the horizontal velocity is constant
When a projectile is launched at an upward angle, its parabolic path is ______ and then ______
Upward Downward
If there is no such thing as a centrifugal force, what causes you to slide to the outside of the seat when riding in an amusement park ride that spins you in circles?
Your body moves to the outside edge of the seat because it has a tendency to travel forward in a straight line as the ride spins in circles