Recent content by cellfoneguy

Homework Statement A football is kicked towards a goal (The little fork thingies, whetever they're called) 10 ft high. The horizontal distance is 52 yards. The initial velocity is 55 mph. Find all angles you can kick the ball at so that it goes over the goal. Homework Equations The...

are the correct values 13.746065934159120354149637745012 for x and 5.4800904540133189355721957718627 for v?

Well, i took x (11.18385807)-v (30.06090238) and got -18.87704431 N. Then i divided by 3.7 (the mass) and got 5.101903868, which is wrong. What?

ok i used the formula to calculate v and x. Then using f=ma, i found the acceleration. I was wrong. I found a mistake, in that in the gravity vector triangle, i used 9.8 which is in m/s^2. After converting it to Newtons, i get that x is 20 something Newtons, which cannot be correct, because then...

Wait, i got a little further on the problem. Knowing that gravity is 9.8, i can find x and y of the gravity vector triangle. x=sin(theta)g=~5.480090454 y=cos(theta)g=~8.124568211 SO now i know x. I need to find v to get the net force, how?

Homework Statement A block is pushed up a frictionless incline by an applied horizontal force as shown. The acceleration of gravity is 9.8 m/s2 . What is the magnitude of the resulting acceleration of the block? Answer in units of m/s^2. Homework Equations...

Sorry, i researched a little and found that sin/cos =tan. I got it now, thanks so much rl.bhat! again.

Hmm, ok. However, for now i only have 2 of those 3 variables, g, and mu. If i wanted to get theta equals something, what i got from deriving is sin(theta)/cos(theta)=mu. So now what do i do? I have sin and cos on one side, so would i take cos^-1(mu)/sin^-1 ? Or what... Also, how would the mass...

Now I'm confused. The normal force is pointing perpendicular to the ramp, right? Why would i need that? And for the g vector along the ramp, i need to find the critical angle, so how could i use it in an equation, unless i can cancel it somehow?

Wouldn't the vector of gravity along the ramp have to exceed the friction for it to move? If it were equal, then the block would be stationary, right? Frictionforce=(mu)mg Frictionforce=(mu)normalforce Also thanks for the quick reply.

Homework Statement No specific question. How would one find the critical angle of a ramp given the mass of the block sliding down it and the mu between ramp and block? It's not a single question but something my teacher explained that i didn't understand. Homework Equations F=(mu)mg F=ma I'm...

AH HA I HAVE IT NOW thanks so much rl.bhat!

hmm. So then the gravity force triangle's theta is...45?

uh...i'm a little confused. so i know that if i get the angle between gravity and the ramp's perpendicular, i can find both the parallel and the perpendicular to the ramp, the two vectors of the gravity force. So i know that to find the force of the block ill need net force. To find net force...

here's both the given info and the FBD i drew