Concept explainers
a .
To find: time when projectile will be back at the ground level.
a .
Answer to Problem 68E
Explanation of Solution
Given:
Initial height
Initial speed
Concept Used:
Position Equation:
Where s represents the height of an object (in feet),
When projectile will be back at the ground level, its height will be
Substitute
This implies that,
Or
So, the projectile will be back at the ground level after
b.
To find: time when projectile’s height will less than 128 feet.
b.
Answer to Problem 68E
Explanation of Solution
Given:
Initial height
Initial speed
Concept Used:
Position Equation:
Where s represents the height of an object (in feet),
Concept Used:
Quadratic Formula:
The zeros of the polynomial
When projectile’s height will less than 128 feet,
Substitute
First step to solve the given inequality is to find the key numbers of the inequality. For that, find zeros of the polynomial
By quadratic formula, zeros of this polynomial are:
Thus, the key numbers are
So, the inequality’s test intervals are
In each test interval, choose a representative x -value and evaluate the polynomial.
Test-Interval | x -value | Polynomial Value | Conclusion |
Negative | |||
Positive | |||
Negative |
The inequality is satisfied for all x -values in
This implies that the solution set of the inequality
Conclusion:
The projectile’s height will less than 128 feet between
Chapter 2 Solutions
EBK PRECALCULUS W/LIMITS
- Calculus: Early TranscendentalsCalculusISBN:9781285741550Author:James StewartPublisher:Cengage LearningThomas' Calculus (14th Edition)CalculusISBN:9780134438986Author:Joel R. Hass, Christopher E. Heil, Maurice D. WeirPublisher:PEARSONCalculus: Early Transcendentals (3rd Edition)CalculusISBN:9780134763644Author:William L. Briggs, Lyle Cochran, Bernard Gillett, Eric SchulzPublisher:PEARSON
- Calculus: Early TranscendentalsCalculusISBN:9781319050740Author:Jon Rogawski, Colin Adams, Robert FranzosaPublisher:W. H. FreemanCalculus: Early Transcendental FunctionsCalculusISBN:9781337552516Author:Ron Larson, Bruce H. EdwardsPublisher:Cengage Learning