Chapter #3

What do we call a projectile that continually "falls"around earth ?

An Earth Satellite

Will A vector ar 45 degrees to the horizontal and vertical components ? By how much ?

Larger ; the vector will be the square root of 2(1.41) times greater than either of the components

Why is it important that such a satellite be above earth's atmosphere ?

To Avoid the heating effects of atmospheric friction .

Neglected air resistance , if you throw a ball straight up with speed of 20m/s, how fast will it be moving when you catch it

20 m/s

If a vector thats is 1cm long represents a velocity of 10km/h, what veelocity does a vector 2cm long drawn to the same scale represent ?

20km/h

A. Neglected air resistance , if you throw a baseball at 20m/s to your friend who is on first base , will the catching speed be greater than , equal to , or less than 20m/s ? B. Does the speed change if air resistance is a factor

A. Equal to B. Yes , it decrease

How Fast must a projectile moving horizontal travel so that the curve of earth ?

About 8 km/s if it is close to earth

What force acts on satellite that is above earth's atmosphere ?

Only Gravity

How does a vector quantity differ from a scalar quantity ?

Only a Vector Quantity is specified by direction .

At What angle should be a slingshot be oriented for maximum altitude ? for maximum horizontal range ?

Straight up; 45 degrees

How does the downward component of the motion of a projectile compare with the motion of free fall ?

Same; both are under the influence of gravity

Why is speed classified as a scalar quantity and velocity classified as a vector quantity ?

Speed has no particular direction ; velocity specifies direction

When a rectangle is constructed in order to add velocities , what represents the resultant of the velocities ?

The Diagonal

Why does a bowling ball move without acceleration when it roll along a bowling alley ?

There is no horizontal component of force

In the absence of air resistance, why does the horizontal components of velocity for a projectile remain constant while the vertical component changes ?

There is no horizontal component of gravitational force

At the instant a ball is thrown horizontally over a level range , a ball held at the side of the first released and drops to the ground . If air resistance is neglected , which ball strikes the ground first ?

They hit the ground at the same time

How Far below an initial straight-line path will a projectile fall in one second ? B. Does your answer depend on the angle of launch or on the intital speed of the project?

a.5m B. No;Vertical displacement below any line is 1/2gt2

Why do we say a rectangle is a special case of parallelogram?

it has four sides , with 2 pairs of sides parallel to each other