- #1

xelrae

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Hello I am new here. I came here because i was trying to search for a tutorial regarding Uniform acceleration motion or UAM but i am so unlucky since i haven't found any decent ones that answers my questions.

An automobile and a race car start from rest at the same instant, with the race car intially behind by 121m. The automobile has a constant acceleration of 2.00m/s^2, and the race car has an acceleration of 3.20m/s^2

a) How much time does it take for the race car to overtake the automobile?

b) Where does the car overtake the automobile?

c) What is the speed of each when they are abreast?

http://en.wikipedia.org/wiki/Equations_of_motion

im sorry for this, i don't know how to put the subscripts and other small symbols :(

EDIT:

v_{ave} = (v_i + v_f)/2

v = v_0 + a t

x = x_0 + v_0 t + (1/2) a t^2

v[itex]^{}[/itex] = v[itex]_{}[/itex][itex]^{}[/itex] + 2 a \Delta x

i don't know how to use the itex thing :( I am sorry

A) my solution for a is simply equating them using the forumla

V=V0t + 1/2(a(t^2)) (i canceled out V0t since the initial velocity is zero)

but adding 121m to the side of the automobile since it is ahead

so that would give me

1/2(3.2)(t^2) = 1/2(2.0)(t^2)+121m

1.6(t^2) = 1(t^2)+121m

0.6(t^2) = 121m

final answer is 14.2

B) x=V0t + 1/2(3.20)((14.2)^2)

again, i canceled out V0t since the initial velocity is zero

so my final answer is about 322.67m

C)

RACE CAR

V^2=V0^2 + 2ad

V^2 = 2(3.2m/s^2)(322m)

V=Square root of 2060.8 m^2/s^2

V=45.40 m/s

AUTOMOBILE

V^2=V0^2 + 2ad

V^2 = 2(2.00m/s^2)(322m)

V=Square root of 1288 m^2/s^2

V=45.40 m/s

There.

My major problem regarding this topic is i don't know WHEN to use WHAT equation.

It really gives me a hard time that's why i resorted to this website in high hopes of finding great understanding. Hope you guys can help me :\ THANKS!

## Homework Statement

An automobile and a race car start from rest at the same instant, with the race car intially behind by 121m. The automobile has a constant acceleration of 2.00m/s^2, and the race car has an acceleration of 3.20m/s^2

a) How much time does it take for the race car to overtake the automobile?

b) Where does the car overtake the automobile?

c) What is the speed of each when they are abreast?

## Homework Equations

http://en.wikipedia.org/wiki/Equations_of_motion

im sorry for this, i don't know how to put the subscripts and other small symbols :(

EDIT:

v_{ave} = (v_i + v_f)/2

v = v_0 + a t

x = x_0 + v_0 t + (1/2) a t^2

v[itex]^{}[/itex] = v[itex]_{}[/itex][itex]^{}[/itex] + 2 a \Delta x

i don't know how to use the itex thing :( I am sorry

## The Attempt at a Solution

A) my solution for a is simply equating them using the forumla

V=V0t + 1/2(a(t^2)) (i canceled out V0t since the initial velocity is zero)

but adding 121m to the side of the automobile since it is ahead

so that would give me

1/2(3.2)(t^2) = 1/2(2.0)(t^2)+121m

1.6(t^2) = 1(t^2)+121m

0.6(t^2) = 121m

final answer is 14.2

B) x=V0t + 1/2(3.20)((14.2)^2)

again, i canceled out V0t since the initial velocity is zero

so my final answer is about 322.67m

C)

RACE CAR

V^2=V0^2 + 2ad

V^2 = 2(3.2m/s^2)(322m)

V=Square root of 2060.8 m^2/s^2

V=45.40 m/s

AUTOMOBILE

V^2=V0^2 + 2ad

V^2 = 2(2.00m/s^2)(322m)

V=Square root of 1288 m^2/s^2

V=45.40 m/s

There.

My major problem regarding this topic is i don't know WHEN to use WHAT equation.

It really gives me a hard time that's why i resorted to this website in high hopes of finding great understanding. Hope you guys can help me :\ THANKS!

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