- #1
RyanJF
- 16
- 0
This is a bit of reading, but the math is simple. I only need my work checked, except for problem number three, in which case I'm simply asking for clarification on which equation I should use.
Problem number one:
"A flower pot falls from a windowsill 25m above the sidewalk. A) How fast is the flower pot moving when it strikes the ground? B) How much time does a passerby on the sidewalk below have to move out of the way of the way before the flower pot hits the ground?"
a = 9.8 (gravity)
x = 25
Vi = 0
Problem number two:
"A plane, starting from rest at one end of a runway, undergoes a constant acceleration of 1.6 m/s^2 for a distance of 1600 meters before takeoff. A) What is its speed upon takeoff? B) What is the time required for takeoff?"
a = 1.6
Vi = 0
x = 1600
Problem number three:
"A boy sliding down a hill accelerates at 1.4m/s^2. If he started from rest, in what distance would he reach a speed of 7/ms?"
a = 1.4
Vi = 0
Vf = 7
Problem number one:
v^2 = Vi^2 + 2ax
Problem number two:
v^2 = Vi^2 + 2ax
Problem number three:
Not sure, that's why I'm asking about it. Possibilities are:
v = Vi + at
x = 1/2 (Vi + V)t
x = Vi x T + 1/2at^2
v^2 = Vi^2 + 2ax
Problem number one:
v^2 = Vi^2 + 2ax
Plugging in numbers for the variables gives me
v^2 = 0^2 + 2 x 9.8 x 25
so
v^2 = 490
sq(490 = 22.135
V = 22.135 m/s
Part b, all I did was:
25/22.135 = 1.129 seconds for the passerby to move out of the way of the falling flower pot.
Problem number two:
v^2 = Vi^2 + 2ax
Plugging in the numbers for the variables gives me
v^2 = 0^2 + 2 x 1.6 x 1600
so
v^2 = 5120
sq(5120
V = 71.554 m/s
For part B, all I did was:
t = Vf - Vi / A
Plugging in the numbers for the variables gives me
t = 71.554 - 0 / 1.6
so
t = 44.72 seconds for the plane to take off
Problem number three:
Not sure of the equation, so I didn't start it.
===
If I didn't already say, all I'd like is to have my answers for problems one and two checked, with an equation(s) supplied for problem number three.
===
Hopefully somebody will help me out here. Thanks!
Homework Statement
Problem number one:
"A flower pot falls from a windowsill 25m above the sidewalk. A) How fast is the flower pot moving when it strikes the ground? B) How much time does a passerby on the sidewalk below have to move out of the way of the way before the flower pot hits the ground?"
a = 9.8 (gravity)
x = 25
Vi = 0
Problem number two:
"A plane, starting from rest at one end of a runway, undergoes a constant acceleration of 1.6 m/s^2 for a distance of 1600 meters before takeoff. A) What is its speed upon takeoff? B) What is the time required for takeoff?"
a = 1.6
Vi = 0
x = 1600
Problem number three:
"A boy sliding down a hill accelerates at 1.4m/s^2. If he started from rest, in what distance would he reach a speed of 7/ms?"
a = 1.4
Vi = 0
Vf = 7
Homework Equations
Problem number one:
v^2 = Vi^2 + 2ax
Problem number two:
v^2 = Vi^2 + 2ax
Problem number three:
Not sure, that's why I'm asking about it. Possibilities are:
v = Vi + at
x = 1/2 (Vi + V)t
x = Vi x T + 1/2at^2
v^2 = Vi^2 + 2ax
The Attempt at a Solution
Problem number one:
v^2 = Vi^2 + 2ax
Plugging in numbers for the variables gives me
v^2 = 0^2 + 2 x 9.8 x 25
so
v^2 = 490
sq(490 = 22.135
V = 22.135 m/s
Part b, all I did was:
25/22.135 = 1.129 seconds for the passerby to move out of the way of the falling flower pot.
Problem number two:
v^2 = Vi^2 + 2ax
Plugging in the numbers for the variables gives me
v^2 = 0^2 + 2 x 1.6 x 1600
so
v^2 = 5120
sq(5120
V = 71.554 m/s
For part B, all I did was:
t = Vf - Vi / A
Plugging in the numbers for the variables gives me
t = 71.554 - 0 / 1.6
so
t = 44.72 seconds for the plane to take off
Problem number three:
Not sure of the equation, so I didn't start it.
===
If I didn't already say, all I'd like is to have my answers for problems one and two checked, with an equation(s) supplied for problem number three.
===
Hopefully somebody will help me out here. Thanks!