An object is launched straight up into the air with an initial velocity of 40 meters per second, from a height 30 m above the ground. How many seconds later will the object hit the ground?

Enter your answer as a number rounded to the nearest tenth, such as: 42.5

8.8 seconds

Step-by-step explanation:

Taking g = 9.81 m/s²

Convention: downwards positive

30 = -40t + 0.5(9.81)t²

4.905t² - 40t - 30 = 0

t = 8.846327763, -0.6913838279

t = 8.8s

use formula for the circle a=3.14

step-by-step explanation:

step-by-step explanation:

if you want to solve percent error follow these steps.

1. subtract the accepted value from the experimental value.

2. take the absolute value of step 1.

3. divide that answer by the accepted value.

4. multiply that answer by 100 and add the % symbol to express the answer as a percentage.

if you want to solve percent of change just do this.

1. work out the difference (increase) between the two numbers you are comparing.

2. divide the increase by the original number and multiply the answer by 100. if your answer is a negative number then this is a percentage decrease.

hope this : )