Deathslayer7

2010-01-24, 05:30 PM

The van travels over the hill described by

y= -.0015(x^2) + 15

If it has a constant speed of 75 ft/s , determine the x and y components of the van's velocity when x= 50 ft.

then determine the x and y components of the vans acceleration at x=50 ft.

A little help with the first part can help me get the second part.

i just took the derivative as it is to get V(y)= -.0015/2*x where x = 50

then i put it in terms of x and did the same thing but got the wrong answer. Anyone know why? :smallconfused:

note: this is a parabola.

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an a different problem that i got half of:

A particle travels along the circular path x^2 + y^2 = r^2

If the y component of the particle's velocity is V(y)=2*r*cos(2t), determine the x and y components of its acceleration at any instant.

I found the right x acceleration after some math, but wouldnt the y acceleration just be the derivative, which is:

-4*r*sin(2t) since r is constant for a circle. I did this and it said it is wrong. Note it is online hw.

Thanks for any help and more problems will come if i have trouble.

y= -.0015(x^2) + 15

If it has a constant speed of 75 ft/s , determine the x and y components of the van's velocity when x= 50 ft.

then determine the x and y components of the vans acceleration at x=50 ft.

A little help with the first part can help me get the second part.

i just took the derivative as it is to get V(y)= -.0015/2*x where x = 50

then i put it in terms of x and did the same thing but got the wrong answer. Anyone know why? :smallconfused:

note: this is a parabola.

-------------------------------------------------------------------------

an a different problem that i got half of:

A particle travels along the circular path x^2 + y^2 = r^2

If the y component of the particle's velocity is V(y)=2*r*cos(2t), determine the x and y components of its acceleration at any instant.

I found the right x acceleration after some math, but wouldnt the y acceleration just be the derivative, which is:

-4*r*sin(2t) since r is constant for a circle. I did this and it said it is wrong. Note it is online hw.

Thanks for any help and more problems will come if i have trouble.