[mthpossom]

Hi, I've got stuck on a mechanics question and I was wondering if anyone would be able to help at all?

First of all I do some work with Newton's second law of motion to get the [simple] differential equations d^2x/dt^2=2 and d^2y/dt^2=3x^2. We're told that the particle starts at rest at the origin at t=0.

The problem is that I have to show that the equation of the trajectory of the particle is y=x^3/10 but I seem to have computed that y=3x^3/2. Anyone know what I've done wrong?

[DFranklin]

Post your working.

[bananarama2]

(Original post by mthpossom)
Hi, I've got stuck on a mechanics question and I was wondering if anyone would be able to help at all?

First of all I do some work with Newton's second law of motion to get the [simple] differential equations d^2x/dt^2=2 and d^2y/dt^2=3x^2. We're told that the particle starts at rest at the origin at t=0.

The problem is that I have to show that the equation of the trajectory of the particle is y=x^3/10 but I seem to have computed that y=3x^3/2. Anyone know what I've done wrong?

You've treated x as a constant and not a function of t. Solve to find x in t and substitute into the second.

[mthpossom]

Thank you very much, I can do it now!