Help with magnitude of net force

[Randy3463]

Homework Statement

A 1700kg car drives around a flat 220m -diameter circular track at 24m/s .

Homework Equations

What is the magnitude of the net force on the car?

The Attempt at a Solution

1700 * (24^2)/(110^2)

i got 80.92561983 round to two sig-figs so 81 and idk why

 

[collinsmark]

Hello Randy3463,

Welcome to Physics Forums.

Homework Statement

A 1700kg car drives around a flat 220m -diameter circular track at 24m/s .

Homework Equations

What is the magnitude of the net force on the car?

The Attempt at a Solution

1700 * (24^2)/(110^2)

You haven't listed any relevant equations.

What is the equation for centripetal force? (Hint: it's not F = mv²/r². Whatever equation you used above has a mistake in it).

Also, don't forget about the gravitational force. That is one of the two components that make up the net force.

 

[Randy3463]

Hello Randy3463,

Welcome to Physics Forums.

You haven't listed any relevant equations.

What is the equation for centripetal force? (Hint: it's not F = mv²/r². Whatever equation you used above has a mistake in it).

Also, don't forget about the gravitational force. That is one of the two components that make up the net force.

i used Fnet= mv^2/(r^2)

Fnet = mrw^2(w=omega)

 

[collinsmark]

Hello Randy3463,

i used Fnet= mv^2/(r^2)

The above equation has a mistake in it.

You can see for yourself by checking the units. Force has units of Newtons in the SI system.

1 [N] = 1 [(kg m)/s²]

But the equation you used ends up with units of [kg/s²], which doesn't make much sense.

Fnet = mrw^2(w=omega)

And ω = v/r. So in terms of v, r, and m, what is centripetal force? (Hint: the r in mrω² cancels out one r in ω²'s denominator.)