Qualification > Math
Mechanics Question
S.M.A.T:
--- Quote from: Dania on October 16, 2010, 11:45:27 pm ---A ball is projected from a point O on the edge of a vertical cliff. The horizontal and vertically upward components of the initial velocity are 7ms-1 and 21ms-1 respectively. At the time t seconds after the projection the ball is at the point (x,y) referred to horizontal and vertically upward axes through O. Air resistance may be neglected.
(i) Express x and y in terms of t, and hence show that y= 3x- 0.1x2
The ball hits the sea at a point which is 25m below the level of O.
(ii) Find the horizontal distance between the cliff and the point where the ball hits the sea.
--- End quote ---
(i) x=7t(horizontal velocity always remain constant so the formula used is s=vt)
y=21t-0.5gt2(s=ut+0.5at2)
t=(x/7)
y=21t-0.5gt2
y=21(x/7) -0.5g(x/7) 2
y=3x-0.1x2
(ii) y=-25(because the question said y is vertically upward axes through O the ball hits below O so negative 25)
3x-0.1x2=-25
0.1x2-3x-25=0
solving this equation we get
x=36.8m
Arthur Bon Zavi:
--- Quote from: asiftasfiq93 on October 17, 2010, 02:48:12 am ---(i) x=7t(horizontal velocity always remain constant so the formula used is s=vt)
y=21t-0.5gt2(s=ut+0.5at2)
t=(x/7)
y=21t-0.5gt2
y=21(x/7) -0.5g(x/7) 2
y=3x-0.1x2
(ii) y=-25(because the question said y is vertically upward axes through O the ball hits below O so negative 25)
3x-0.1x2=-25
0.1x2-3x-25=0
solving this equation we get
x=36.8m
--- End quote ---
Have You Completed yous A Levels? :D
S.M.A.T:
--- Quote from: Ancestor on October 17, 2010, 07:25:34 am ---Have You Completed yous A Levels? :D
--- End quote ---
no,still doing my A2.:)
Arthur Bon Zavi:
--- Quote from: asiftasfiq93 on October 18, 2010, 10:55:13 am ---no,still doing my A2.:)
--- End quote ---
Well Then Go Ahead! 8)
astarmathsandphysics:
they found the angle between south and the 6N force and resolved vertically
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