Mechanics Question

[S.M.A.T]

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.

(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]

(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

   

Have You Completed yous A Levels?

[S.M.A.T]

Have You Completed yous A Levels?

no,still doing my A2.

[Arthur Bon Zavi]

no,still doing my A2.

Well Then Go Ahead! 

[astarmathsandphysics]

they found the angle between south and the 6N force and resolved vertically

[Ghost Of Highbury]

attached

Can u help with the second subpart too plz?

Y do they use F = T cos (sin^-1 0.6)

[elemis]

Can u help with the second subpart too plz?

Y do they use F = T cos (sin^-1 0.6)

What question are you referring to ?

[Ghost Of Highbury]

iVE quoted it.

[elemis]

iVE quoted it.

But whats the ORIGINAL question ? All you've quoted is the answers Nid gave you - I cant find your question anywhere.

[Ghost Of Highbury]

But whats the ORIGINAL question ? All you've quoted is the answers Nid gave you - I cant find your question anywhere.

Click on the "Quote from...." mate.

[Ghost Of Highbury]

I know that the Friction force is stopping the ring to slip and opposing T too.

I think it should be F = T + Wsin53.1 (weight component)

But the answer seems to ignore the W, and instead give the equation F = Tsin53.1

[elemis]

Click on the "Quote from...." mate.

I did that. I'm not dumb you know....

I figured out you were talking about Dania's question.

This whole time I was looking for a question posted by YOU.

[Ghost Of Highbury]

I did that. I'm not dumb you know....

I figured out you were talking about Dania's question.

This whole time I was looking for a question posted by YOU.

Ahh ok.

[Deadly_king]

I know that the Friction force is stopping the ring to slip and opposing T too.

I think it should be F = T + Wsin53.1 (weight component)

But the answer seems to ignore the W, and instead give the equation F = Tsin53.1

W acts perpendicular to the ring...............hence it has no component!

[Ghost Of Highbury]

W acts perpendicular to the ring...............hence it has no component!

Could you elaborate that plz, and sry for the trouble.