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    A sprinkler on horizontal ground is projecting drops of water from ground level in all directions. The water droplets all have an initial speed of 15 m/s
    i)calculate the height reached by a water droplet projected vertically upwards
    ii) what can you say about the height reached by water droplets projected at other angles, explain your answer briefly

    I've worked out that the displacement of the vertical component is 15sin theta -5t^2, and I thought that theta would be 90 degrees to the x axis when projected vertically. Really don't know the answer!?
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    (Original post by imaan2121)
    A sprinkler on horizontal ground is projecting drops of water from ground level in all directions. The water droplets all have an initial speed of 15 m/s
    i)calculate the height reached by a water droplet projected vertically upwards
    ii) what can you say about the height reached by water droplets projected at other angles, explain your answer briefly

    I've worked out that the displacement of the vertical component is 15sin theta -5t^2, and I thought that theta would be 90 degrees to the x axis when projected vertically. Really don't know the answer!?
    If it's projected vertically upwards you can just consider the vertical motion on it's own, that's okay. In this case, u is just 15, as it is 15ms-1 in the vertical direction, so there is no angle between the direction of motion and the vertical
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    (Original post by imaan2121)
    A sprinkler on horizontal ground is projecting drops of water from ground level in all directions. The water droplets all have an initial speed of 15 m/s
    i)calculate the height reached by a water droplet projected vertically upwards
    ii) what can you say about the height reached by water droplets projected at other angles, explain your answer briefly

    I've worked out that the displacement of the vertical component is 15sin theta -5t^2, and I thought that theta would be 90 degrees to the x axis when projected vertically. Really don't know the answer!?
    you missed out a t in the formula:

    (15sin Θ)t -5t2

    [it might by 4.9 instead of 5]

    now you need to think about the vertical velocity at time t....

    and especially what value it takes at the top.
 
 
 
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