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