Question

a bus travels at 25m/s and attempts to jump over a space between two parts of an unfinished bridge.the gap between the two points is 20m and the two are the same elevation.ehat minimum angle must the bus take off in order to make jump?

Answer 1

can u help me

Answer 2

jesus this is an annoying problem lol I hate angle problems!

Answer 3

:-(

Answer 4

too bad it doesn't give you a height that it reaches

Answer 5

they gave me x=20m and v=25m/s

Answer 6

i got answer as 9 degree

Answer 7

is that right

Answer 8

sec trying to work this out in my head kinetics has been a while

Answer 9

units are in meters
so we can use gravity constant g =9.8 m/s^2

we know the distance that needs to be cleared is 20 meters

Answer 10

lets start by looking at the x direction
no acceleration
only velocity
distance travelled will be 20m
we can use x=vt

20=(25 cos(theta))* t

Answer 11

ok

Answer 12

now lets look at the y position

acceleration is g=-9.8m/s^2
velocity is v=25 sin(theta)

the 2 points, where the bus leaves and lands are the same elevation/height
we can call that x0=0 and y=0 at time t

so we use
y=1/2at^2+vt+c

0=-1/2(9.8)t^2 +25 sin(theta)

Answer 13

0=-1/2(9.8)t^2 +25 sin(theta)t

Answer 14

Yeah thats exactly what I was doing but my internet cut out lol

Answer 15

now we have a system of 2 equations with 2 unknowns,

suggestion would be to solve for t and substitute

Answer 16

@completeidiot i got angle as 9

Answer 17

excatly i did that one i am not sure about algebra

Answer 18

i didnt actually solve the problem and i dont want to

too much work

Answer 19

I got to 4.9 (20/(25cosx))^2 + 20 tanx= 0 then I got side tracked doing bio

Answer 20

suggestion- if you have a graphing calculator
ti-84

graph the equation and find the root using the zero function

Answer 21

i know that but how do u find angle i can find time

Answer 22

x direction
20=(25 cos(theta))* t

t=20/(25 cos(theta))

Answer 23

so how do u graph this

Answer 24

how do u put theta in it

Answer 25

theta =x

Answer 26

in calcu;ator

Answer 27

ok i will try

Answer 28

minimum angle of 9.138 degrees

Answer 29

so am i right?

Answer 30

well 9.138 > 9

yes, if you just rounded to the ones place

technically no, if you actually attempted doing this, the bus would hit the cliff, everyone would die and it would fall to its doom or blow up