here are the score that Jenna has received on her seven quizzes 16 13 20 16 12 17 18 what is the mean
1 answer:
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Answer:
Step-by-step explanation:
We are given the position function and need to find the value of t when h<17.
Create an inequality that represents this situation:
The "less than" sign makes this very specifically a conjunction problem as opposed to a disjunction. That's important to the solution. But we'll get there.
The simplest way to solve this is to subtract 81 from both sides:
then divide both sides by -16:
Notice now that the sign is facing the other way since we had to divide by a negative number. Now it's a disjunction. The solution set to this inequality is that t>2 or t<-2. First and foremost, time will never be negative, so we can disregard the -2. Even if that was t<2, the more time that goes by, the greater the time interval is, not the lesser. It's the "<" that doesn't make sense, not only the -2. The solution to this inequality is
t > 2 sec. That means that after 2 seconds, the height of the ball is less than 17 feet.
Answer:
(a) 25.08 m
(b) 2.05 m
Step-by-step explanation:
Let the height of the building be 'h'.
Given:
Angle of projection is, °
Initial speed is,
Time of flight is,
(a)
Consider the vertical motion of the brick.
Vertical component of initial velocity is given as:
Vertical displacement of the brick is equal to the height of the building.
So, vertical displacement = (Negative sign implies downward motion)
Acceleration is due to gravity in the downward direction. So,
Acceleration is,
Now, using the following equation of motion;
Therefore, the building is 25.08 m tall.
(b)
Let the maximum height be 'H'.
At maximum height, the vertical component of velocity is 0 as the brick stops temporarily in the vertical direction.
So,
Now, using the following equation of motion, we have:
Therefore, the maximum height of the brick is 2.05 m.