1. The problem statement, all variables and given/known data A father gives his daughter a ride on a sled by applying a force F at an angle θ = 26.0° with respect to the horizontal. If the coefficient of static friction is µs = 0.153, and the combined mass of sled and child is m = 24.0 kg What is the minimum amount of force required to move the sled from rest by pulling it 2. Relevant equations F=ma 3. The attempt at a solution I have tried multiple ways and i keep getting the wrong answer, I think i should take the sum of all the forces in the x direction and of the y direction and somehow get the force i need but im not exactly sure. HELP PLEASE? 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution
Re: Given the mass, angle, and the coefficient of static friction, find the pulling f The words "minimum amount of force" and "from rest" imply that this is a statics problem. In statics, what is the special condition on the net force? What does the word "static" imply about the value of the acceleration in f=ma? Once you figure that out, you should have your net x force components (which requires trig) sum to this special value for the net force as well as you net y force components (which also requires trig). EDIT: Also make sure you have your pulling force in the correct direction. Did you draw a free body diagram?
Re: Given the mass, angle, and the coefficient of static friction, find the pulling f So "static" would imply that the value of acceleration =0 ?right? so i have in the x direction: F(pull,x) + F(friction,x) +W(x) + n(x) = 0 but there is no W or F(gravity) in the x direction so that equals zero and same for n(x) (normal force) =0. therefore i have: F(pull,x) +f(friction,x)=0 right? In the y direction: F(pull,y) + F(friction,y) +W(y) + n(y) = 0 F(friction,y)=0 therefore i have: F(pull,y) +W(y) + n(y) = 0 right? then F(pull,x) = F(pull)cosθ and F(pull,y) =F(pull)sinθ I all that ive said is correct now, what would i do now? or is there other things that i am missing ?
Re: Given the mass, angle, and the coefficient of static friction, find the pulling f Since the force is pulling, is your pulling force positive or negative? Is your weight positive or negative? I see two equations and two unknowns (Fpull and normal). Pull out your algebra toolkit and solve it.
Re: Given the mass, angle, and the coefficient of static friction, find the pulling f thanks for your help, i got the answer :P