I asked a question concerning this a while ago, but now it's a little different...

A student gets a cart that does not suffer drag. Now, though, the track is not leveled.

How can I calculate the angle?

The cart is on an inclined plane, then there is a pully, and a load. So the angle trying to be found is the inclination of the plane which the cart is on with the.

The knowns are:
cart 7.6kg
load 4.2kg
acc 1.2kg

I know I have to use components... but I just don't know how to incorporate them with Newton's II Law.

To calculate the angle of the inclined plane, you can use the concepts of forces and Newton's second law. Here's how:

Step 1: Draw a diagram illustrating the forces acting on the cart. On the inclined plane, you have four forces at play:
- The weight of the cart, which acts straight downwards.
- The normal force, which acts perpendicular to the surface of the inclined plane.
- The force of tension in the string or rope that connects the cart to the load, which acts parallel to the inclined plane.
- The force of friction, which acts parallel to the inclined plane but in the opposite direction of motion.

Step 2: Break down the weight of the cart into its components. The weight has two components: one that acts perpendicular to the inclined plane (mg * cosθ) and another that acts parallel to the inclined plane (mg * sinθ). Here, m is the mass of the cart and g is the acceleration due to gravity.

Step 3: Apply Newton's second law in the direction perpendicular to the plane. In this direction, the sum of the forces should be equal to zero since the cart is not moving vertically. The forces acting in this direction are the normal force (N) and the perpendicular component of the weight. So you have: N - mg * cosθ = 0.

Step 4: Apply Newton's second law in the direction parallel to the plane. In this direction, the sum of the forces should be equal to the mass of the cart multiplied by its acceleration. The forces acting in this direction are the force of tension (T), the parallel component of the weight, and the force of friction (f). So you have: T - mg * sinθ - f = ma, where a is the acceleration of the cart.

Step 5: Determine the force of friction using the coefficient of friction (μ) and the normal force. The force of friction can be calculated as: f = μN.

Step 6: Solve the system of equations formed in steps 3 and 4 to find the unknown variable, which is the angle θ in this case. You can substitute the expression for the force of friction (f) from step 5 into the equation in step 4. Rearrange the equation to isolate sinθ and solve for θ.

Note: The acceleration (a) you mentioned in the knowns is not used in the above procedure. If you have additional information or if there are any other details you'd like to include, feel free to update the question so that the answer can be tailored accordingly.