![dayaa67](/avatars/30518.jpg)
dayaa67
23.06.2020 •
Mathematics
A boy is playing a ball in a garden surrounded by a wall 2.5 m high and kicks the ball vertically up from a height of 0.4 m with a speed of 14 m/s . For how long is the ball above the height of the wall.
Solved
Show answers
More tips
- H Health and Medicine How does childbirth happen: everything future mothers need to know...
- H Horoscopes, Magic, Divination Is there a 13th Zodiac Sign?...
- H Health and Medicine Want to Lose Weight? Gain Muscle without Damaging Your Health!...
- F Family and Home Parquet or laminate, which is better?...
- L Leisure and Entertainment How to Properly Wind Fishing Line onto a Reel?...
- L Leisure and Entertainment How to Make a Paper Boat in Simple Steps...
- T Travel and tourism Maldives Adventures: What is the Best Season to Visit the Luxurious Beaches?...
- H Health and Medicine Kinesiology: What is it and How Does it Work?...
- O Other How to Choose the Best Answer to Your Question on The Grand Question ?...
- L Leisure and Entertainment History of International Women s Day: When Did the Celebration of March 8th Begin?...
Answers on questions: Mathematics
- M Mathematics 1. Write short notes on reuse ...
- M Mathematics Can someone help, picture above...
- M Mathematics Acarpenter builds stools that have 3 legs each how many legs does the carpenter use to build 5 stools use array to explain how you know your answer is correct...
- H History List the six steps to become a nationalised citizen?...
- H History Which can employers use to prevent an industrial action by a union from affecting productiona. strikebreakersb. social securityc. wage cutsd. collective bargaining...
- C Computers and Technology Which of the following is NOT a form of technology? A log raft Wooden canoe Stone knife Blowing wind...
- M Mathematics Which number line shows the correct placement of 20%, 1/3, and 2/3?...
Ответ:
2.5 sec
Step-by-step explanation:
Height of wall = 2.5 m
initial speed of ball = 14 m/s
height from which ball is kicked = 0.4 m
we calculate the speed of the ball at the height that matches the wall first
height that matches wall = 2.5 - 0.4 = 2.1 m
using = + 2as
where a = acceleration due to gravity = -9.81 m/s^2 (negative in upwards movement)
= + 2(-9.81 x 2.1)
= 196 - 41.202
= 154.8
v = = 12.44 m/s
this is the velocity of the ball at exactly the point where the wall ends.
At the maximum height, the speed of the ball becomes zero
therefore,
u = 12.44 m/s
v = 0 m/s
a = -9.81 m/s^2
t = ?
using V = U + at
0 = 12.44 - 9.81t
-12.44 = -9.81
t = -12.44/-9.81
t = 1.27 s
the maximum height the ball reaches will be gotten with
= + 2as
a = -9.81 m/s^2
0 = + 2(-9.81s)
0 = 196 - 19.62s
s = -196/-19.62 = 9.99 m. This the maximum height reached by the ball.
height from maximum height to height of ball = 9.99 - 2.5 = 7.49 m
we calculate for the time taken for the ball to travel down this height
a = 9.81 m/s^2 (positive in downwards movement)
u = 0
s = 7.49 m
using s = ut + a
7.49 = (0 x t) + (9.81 x )
7.49 = 0 + 4.9
= 7.49/4.9 = 1.53
t = = 1.23 sec
Total time spent above wall = 1.27 s + 1.23 s = 2.5 sec
Ответ:
£625.44
Step-by-step explanation:
100×13.03%×48