posted by Leo on .
Two horizontal forces F1 and F2 act on a 1.7 kg disk that slides over frictionless ice, on which an xy coordinate system is laid out. Force F1 is in the negative direction of the x axis and has a magnitude of 3.0 N. Force F2 has a magnitude of 9.0 N. What is the angle between the constant directions of forces F1 and F2?
what is the formula??? or proceedure?? ty :)
Based on the velocity vs time graph we can create a slope and equation of the line. The slope is y2-y1/x2-x1 or (5+4)/(3-0). This gives us a slope of 3. The y intercept of the V vs T graph is -4 so our Vx equation is 3t-4. The derivative of this equation is 3m/s^2 which gives us the x component of acceleration. Using the formula ∑F=ma we try to find the sum of the forces in the x direction. We already know one of the forces (F1) is 7N in the x direction since it is given. We now need to find the other one based off of F2. To find the x component we take 9cosӨ=F2x. Now we plug these into the formula ∑F=ma and get 7+9cosӨ=4kg•3 where 4 is our mass and 3 is our x component of acceleration. Using algebra you get theta to be 56.25 degrees.
Correction to my previous post, substitute 4kg for 1.7 kg and flip the x values to the negative since they are pointing in the negative x direction. It is still the same concept though.