20 m/s

A player kicks a football straight up into the air. The ball takes 2.0 s to reach its highest point. Approximately how fast was the ball moving when it left the player’s foot?

magnitude

The ______ of a vector is always a positive quantity.

right, up

Ax is positive if Ax is directed _______; Ay is positive if Ay is directed _______.

angle of the ramp

The acceleration of a cart rolling down a ramp depends on

is directed down at all times

The acceleration vector of a particle in projectile motion

points towards the center of the circle

a=v²/r

a=v²/r

The acceleration vector of a particle in uniform circular motion

tangent to the path

The velocity vector of circular motion is

magnitude

Ax is the __________ of the vector Ax

5m/s

pythagorean theorem 3-4-5 triangle!

A factory conveyor belt rolls at 3 m/s. A mouse sees a piece of cheese directly across the belt and heads straight for the cheese at 4 m/s. What is the mouse’s speed relative to the factory floor?

they hit the ground at the same time

A heavy red ball is released from rest 2.0 m above a flat, horizontal surface. At exactly the same instant, a yellow ball with the same mass is fired horizontally at 3.0 m/s. Which ball hits the ground first?

2.0m

A 100-g ball rolls off a table and lands 2.0 m from the base of the table. A 200-g ball rolls off the same table with the same speed. It lands at distance

yes

A car is traveling around a curve at a steady 45 mph. Is the car accelerating?

4

A toy car moves around a circular track at constant speed. It suddenly doubles its speed — a change of a factor of 2. As a result, the centripetal acceleration changes by a factor of

point in the direction of displacement

Velocity vectors

Ay= Asinθ

Ax= Acosθ

θ= tan-1 (Ay/Ax)

magnitude of A= √(Ax²+ Ay²)

signs depend on direction of vector

Ax= Acosθ

θ= tan-1 (Ay/Ax)

magnitude of A= √(Ax²+ Ay²)

signs depend on direction of vector

Vector components

object acceleration and velocity are parallel to the surface

signs depend on tilt direction

ax=± gsinθ

signs depend on tilt direction

ax=± gsinθ

Motion on ramp

(vx)O2-O1=(vx)O2-surface + (vx)O1-surface

Relative Motion speed of object 2 with respect to object 1

path is a parabola

object moves through 2 dimesnion under influence of gravity and nothing else

vertical motion with free fall acceleration ay=-g and (vy)i= vi sinθ

horizontal motion with constant velocity (vx)i= vi cosθ

object moves through 2 dimesnion under influence of gravity and nothing else

vertical motion with free fall acceleration ay=-g and (vy)i= vi sinθ

horizontal motion with constant velocity (vx)i= vi cosθ

Projectile motion