Urgent help needed, question inside (1 Viewer)

[Twickel]

Hi
I need to calculate the initial and final velocity of a marble.

This marble was allowed to roll down a ramp then on about 20cm of the top of a step then it fell down the step, the step was 0.5m high

I have delta x ( horizontal displacement)
and I have delta y ( vertical displacement)


Thanking you all.

 

[4theHSC]

easy,, not going to answer till you put it in the right place dude,, you did that twice now.

 

[Twickel]

Urgent help needed, question inside.

Hi
I need to calculate the initial and final velocity of a marble.

This marble was allowed to roll down a ramp then on about 20cm of the top of a step then it fell down the step, the step was 0.5m high

I have delta x ( horizontal displacement)
and I have delta y ( vertical displacement)


Thanking you all.

 

[Twickel]

OK I put it in the physics forum, can you help me?


Then ill delete this.

Sorry I remember in the prelim forum we used to be able to ask questions related to any subject... maybe cause exams were near.

 

[3unitz]

Re: Urgent help needed, question inside.

delta y = u_yt + (1/2)gt^2

-0.5 = -(1/2)gt^2

t = sqrt(1/g) (time of flight)

delta x = u_xt

u_x = (delta x) / sqrt(1/g)

y component of the final velocity:

v_y = u_y + gt

v_y = g . sqrt(1/g) (down)

final velocity using vector addition:

v_final^2 = [(delta x) / sqrt(1/g)]^2 + [g . sqrt(1/g)]^2

v_final = sqrt [g(delta x)^2 + g]

at angle @ = tan^-1 [v_y / v_x]

= tan^-1 [1/(delta x)] to the horizontal

 

[Twickel]

Re: Urgent help needed, question inside.

I dont have time of flight though

Say delta x = 0.51m

how do I figure out the velocity using your method?

Sub it in please?

 

[Twickel]

Re: Urgent help needed, question inside.

I get ux= 1.56m/s

so this takes into account friction ari resistance etc?
because the theoretical ux value was 3.28 using ur way I get half of that is that correct?


Theoretical range should have been 0.75m actual range is 0.51 I need to find out the velocity of the ball for the 0.51m, as this take in to account the air resistace and stuff.

 

[Twickel]

Re: Urgent help needed, question inside.

Then howcome I get the same time of flight?


For theoretical time of flight and practical time of flgiht ( using ur method I still get 0.32s)

And using ur method I get the same theoretical y velocity and same practical y velocity, the only thing that changes is the x velocity.

I would have thought vy and time of flight would have changed once air resistance + friction is taken into account

 

[Twickel]

Re: Urgent help needed, question inside.

I did a prac to compare theoretical and practical values, I let a marble roll down a ramp then on some stright piece of ground ( top of step) and it then fell down the step.

When the ramp was at an angle of 24 degrees, its theoretical time of flight, horizontal velocity and vertical veloicty were 0.32s, 2.87ms, 3.13ms

The theoretical range should have been 0.92m but it only travelled 0.64 m how can I figure out what the velocity of the marble was when it travelled the 0.64m?