? asked in Science & MathematicsPhysics · 1 decade ago

PHYSICS: pls help me with this?

A car falls off a ledge and reaches the ground in 0.5 seconds, take g = 10m/s^2

1. What is its speed on striking the ground?

2. What is its average speed during 0.5 sec?

3. How high is the ledge from the ground?

Whoever answers first i will choose that answer as best answer. pls answer ASAP.

tnx

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  • 1 decade ago
    Favorite Answer

    Write out variables:

    U (initial velocity) = 0

    V (final velocity) = Find out

    G = 10 (acceleration)

    T = 0.5

    S = Displacement

    v=u + at

    v^2 = u^2 + 2as

    s = ut + 1/2 a t^2

    1)

    we are going to use v = u + at

    v = 0 + 10 * 0.5

    v = 5ms^-1

    2)

    average speed is equal to distance over time

    S = distance

    s = ut+1/2 at^2

    s = 0*0.5 (strike out) + 0.5*10*0.5^2

    s= 5 * 0.5^2

    s = 5*0.25

    s = 1.25ms^-1

    S/T = ave speed

    1.25/0.5 = 2.5 ms^-1

    3)

    1.25 metres. We established that earlier.

    Hoped i helped!! :)

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  • 1 decade ago

    (3) Let the height of the ledge is h meter

    =>By s = ut + 1/2gt^2

    =>h = 0 + 1/2 x 10 x (0.5)^2

    =>h = 1.25 m

    (1) By v = u + gt

    =>v = 0 + 10 x 0.5

    =>v = 5 m/s

    (2) By average velocity (u) = h/t = 1.25/0.5 = 2.5 m/s

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  • 1 decade ago

    Ok, initiall assumptions:

    - the car's initial velocity is: v0 = 0 (both on horizontal and vertical axis);

    - there is no friction with the air during the fall;

    Solution:

    v = v0 + g * t;

    1. Upon striking the ground: v(0.5) = 5 [m/s];

    3. The motion law in accelerated motion is:

    x = x0 + v0 * t + (a * t^2) / 2;

    x(0.5) = 1.25 [m];

    2. The average velocity is:

    vav = x / t;

    vav(0.5) = x(0.5) / 0.5t = 2.5 [m/s].

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  • ?
    Lv 4
    1 decade ago

    1. striking the ground its 0 m/s

    2. v = a*t + V0, v=0.5*10 = 5 m/s

    3. d=v*t, d= 5*0.5= 2.5 m

    hope i helped

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  • 1 decade ago

    for part 1: t= 0.5s. a=10m/s^2

    s = ut + 0.5at^2 = 0 + 0.5*10*0.5^2 = 1.25m/s

    part 2: s=d/t

    v = u+at = 0.5*10 = 5m/s

    part 3: s = d/t --> d=ts = 0.5*5 = 2.5m

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