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Old Sep 23rd 2008, 02:09 PM   #1
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motion

a projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of 65.0 m at an angle of 35 with the horizontal.

(a) Determine the time taken by the projectile to hit point P at ground level.

(b) Determine the distance X of point P from the base of the vertical cliff

(c) At the instant just before the projectile hits point P, find the horizonal and the vertical components of its velocity

(d) the magnitude of the velocity

(e) the angle made by the velocity with the horizonal

(f) find the max height above the cliff top reached by the projectile

My attempt
(a) t1 = vy/g = 3.8 sec
t2 = square root of (2 X s / g) = 6.2
for s i did s= 115 + 37 X 3.8 + (1/2)(9.81)3.8^2
s= 185
T = t1 + t2 = 3.8 + 6.2 = 10
(b) distance = t X Vx
10 X 53 = 531

(f) is s = 185

and im completely lost on c , d, e
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Old Sep 23rd 2008, 09:47 PM   #2
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quote=whazzap88;1471]a projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of 65.0 m/s at an angle of 35 with the horizontal.

(a) Determine the time taken by the projectile to hit point P at ground level.

(b) Determine the distance X of point P from the base of the vertical cliff

(c) At the instant just before the projectile hits point P, find the horizonal and the vertical components of its velocity

(d) the magnitude of the velocity

(e) the angle made by the velocity with the horizonal

(f) find the max height above the cliff top reached by the projectile

[/quote]
I don't know whether I'm correct or not.

a) $\displaystyle s_y=u_yt-gt^2/2$
$\displaystyle -115= 65sin35^ot-9.8t^2/2$
$\displaystyle t= 9.96s$cor to 3 sig fig

b) $\displaystyle s_x= u_xt $
$\displaystyle s_x=65cos35^o(9.964068986)$
$\displaystyle s_x=560 m$cor to 3 sig fig

c) As there is no acceleration in horizontal direction, therefore x-component of velocity is = $\displaystyle 65cos35^o$

For y- component of velocity,
$\displaystyle v_y=u_yt-gt$
$\displaystyle v_y= 65sin35^o-(9.8)(9.964068986)$
$\displaystyle v_y=-60.3m/s$cor. to 3 sig fig

d)$\displaystyle v^2=v_x^2+ v_y^2$
$\displaystyle v=80.5m/s$cor. to 3 sig fig

e) angle required=$\displaystyle tan^-1(v_y/v_x)$
angle required = $\displaystyle 48.6^o$

f) $\displaystyle v^2-u^2=2gh$
$\displaystyle 0-(65sin35)^2=-2(9.8)h$
$\displaystyle h=70.9m$cor. to 3 sig. fig.
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Old Sep 23rd 2008, 11:16 PM   #3
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for (b) isnt it 531 rather than 560.. is it typo????
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Old Sep 24th 2008, 08:10 AM   #4
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Originally Posted by whazzap88 View Post
a projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of 65.0 m at an angle of 35 with the horizontal.

(a) Determine the time taken by the projectile to hit point P at ground level.

(b) Determine the distance X of point P from the base of the vertical cliff

(c) At the instant just before the projectile hits point P, find the horizonal and the vertical components of its velocity

(d) the magnitude of the velocity

(e) the angle made by the velocity with the horizonal

(f) find the max height above the cliff top reached by the projectile

My attempt
(a) t1 = vy/g = 3.8 sec
t2 = square root of (2 X s / g) = 6.2
for s i did s= 115 + 37 X 3.8 + (1/2)(9.81)3.8^2
s= 185
T = t1 + t2 = 3.8 + 6.2 = 10
(b) distance = t X Vx
10 X 53 = 531

(f) is s = 185

and im completely lost on c , d, e
b) The method is right, but I'm getting 530 m.

The rest looks good.

-Dan
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projectile 115 m above initial V=65m/s angle 35 horizontal calculate maximum hieght above cliff
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A projectile is shot from the edge of a clift 115 m above the ground level with an initial speed of 65.0 m/s

,

a projectile is shot from the edge of a cliff 115 m above

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a projectile is shot from the edge of a cliff 115m above ground level with an initial speed of 65.o m/s at an angle of 35.o degrees horizontal. Find the horizontal and vertical components of its velocity.

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a projectile is shot from the edge of a cliff 125metres above the ground with an initial speed of 65m/s an an angle 37 from the horizontal

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A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of 65.0 m/s at an angle of 35.0° with the horizontal, as shown in Fig. 2. 2.1 Determine the time taken by the projectile to hit point P at ground level.

,

A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of 65.0 m/s at an angle of 35.0° with the horizontal, as shown in Fig. 2. 2.1 Determine the time taken by the projectile to hit point P at ground level.

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a projectile is shot from the edge of a cliff

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A projectile is shot from the edge of a cliff 115 m above ground level with an initial speed of 65.0 m/s at an angle of 35.0° with the horizontal, as shown in Fig. 2. 2.1 Determine the time taken by the projectile

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A projectile is short from the edge of a cliff 125m above the ground with an initial speed of 65m/s at an angle of 37 degrees.determine the time taken by the projectile to hit point P at ground level

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a projectile is shot from tje edge of a Cliff 125 m above ground level with an initial speed of 65.0 m/s at an angle of 37 degrees with the horizontal

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