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