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projectile motion

a ball is hit when it is at a height of 0.400m. it just clears the tennis net, travelling horrizontally and then lands on the ground at a distance of 11.9m from the net.
(a) show that the horizontal component of velocity of the ball is about 30ms

i just simply dont know what to do
(edited 2 years ago)
Original post by Mustafah41352
a ball is hit when it is at a height of 0.400m. it just clears the tennis net, travelling horrizontally and then lands on the ground at a distance of 11.9m from the net.
(a) show that the horizontal component of velocity of the ball is about 30ms

i just simply dont know what to do

Use SUVAT and the information ....

You need to attempt the question before we can help :smile:
Original post by Muttley79
Use SUVAT and the information ....

You need to attempt the question before we can help :smile:

i dont know where to start.
the most i can do is S=11.9 U=0 a=9.8. im dont really understant at all.
(edited 2 years ago)
Original post by Mustafah41352
i dont know where to start.
the most i can do is S=11.9 U=0 a=0. im dont really understant at all.

And vertically?
Original post by Muttley79
And vertically?

so vertically would be 0.91-0.4=0.51
Original post by Mustafah41352
so vertically would be 0.91-0.4=0.51

Why is u= 0 btw?

Where do these numbers come from? What is u and a ?
Original post by Muttley79
Why is u= 0 btw?

Where do these numbers come from? What is u and a ?

i guess they are assuming the value of a and u.well shouldn't we use Fcostheta to find the horizontal component?
Original post by Muttley79
Why is u= 0 btw?

Where do these numbers come from? What is u and a ?

u is initial velocity, but i dont know how to get that, and a is acceleration but since im finding the horizontal it is 0?
Original post by Fareeha18
i guess they are assuming the value of a and u.well shouldn't we use Fcostheta to find the horizontal component?

We only need to show the horiz component 'is about 30' so I would just call it 'u'
Original post by Mustafah41352
u is initial velocity, but i dont know how to get that, and a is acceleration but since im finding the horizontal it is 0?

I've done the question - have you now?
Original post by Muttley79
I've done the question - have you now?

i think so, so S=0.91 U=0 a=9.8 put into s=ut+1/2 a t^2 t=0.43 then v=d/t to get 27.

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