The height s of a ball after t seconds when thrown straight up with an initial speed of 70 feet per second from an initial height of 5 feet can be modeled by the function s(t)=-16t^2 +70t +5
(a) When will the height of the ball be 50 feet?
(b) When will the height of the ball be 70 feet?
(c) Will the ball ever reach a height of 130 feet?

step-by-step explanation:

1. practice, practice & more practice

2. review errors

3. master the key concepts

do not try to memorise the processes.

4. understand your doubts.

5. create a distraction free study environment

6. create a mathematical dictionary

7. apply maths to real world problems.

54 kilometers per hour

step-by-step explanation:

according to rules:

1 km = 1000 meter

which means that 1 meter = 1/1000 km

1 hour = 3600 second [ as 1 hour = 60 min = 60 *60 seconds ]

which means that 1 second = 1/3600 hour

therefore, 1 kilometer/hour =

thus to convert 15 meter per second to kilometer per hour, we multiply 15 to 3.6 kilometer/hour.

15 meter/second=   which is the required answer.