# Force and Newton law of Motion

hi there i have a question in which i can't get the answer i will show my work on what i did, if anybody can help , that would help alot .

here is the question:

only two forces act on an object (mass= 3kg)

x=40N
a=60N is at 45 degrees above the horizon
y= ?
find the magnitude and direction (relative to the x-axis) of the acceleration of the object?

i can use (a=60N)sin(45)= 42.42degrees, but where do i go from here, or whats the next step, i did try squaring y+x under the square root, but thats not the magnitude, because the answer in teh back of the book is different.

any help is welcome thanks

Ok first of all the 42.42 value wont be in degrees, it will be in newtons. Secondly, draw a diagram, it always helps.

In order to help you more i need to know which direction the x force is in. so draw up what you think is happeneing and then attach it.

In essence you are just resolving vector components of a force, and need to draw a few triangles and stuff to find the resultant

andrevdh
Homework Helper
Newton's second law can be applied in component form:

$$\Sigma F_x = ma_x$$

that is

$$a_x = \frac{\Sigma F_x}{m}$$

so to get the acceleration in the x-direction you need to add the force components acting on the object in the x-direction and divide that by its mass.