Final answer:
To calculate the work done by each force on the block, you need the horizontal component of the pull force and the force of friction. Work is the product of force and displacement in the direction of force. Friction does negative work as it acts in the opposite direction to motion.
Step-by-step explanation:
The question is looking to determine the work done by each force acting on a 4kg block that is pulled by a 40 N force over a horizontal distance of 8m at a 35° angle, with a coefficient of kinetic friction (μₖ) of 0.2. To find the work done by each force, we need to consider the component of the force in the direction of motion and the distance over which the force is applied.
To calculate the work done by the pull force W₁, we use the component of the 40 N force that is parallel to the horizontal motion. This is calculated as Fₓ = F cos(θ), where F is the magnitude of the force and θ is the angle of the force with respect to the horizontal. After getting the parallel component, we multiply it by the distance, d, to find the work done W₁ = Fₓ × d.
For the work done by friction Wₒ, we first find the normal force, which is reduced due to the pulling angle: N = mg - F sin(θ). The friction force Fₖ is μₖ × N. The work done by friction is Wₒ = Fₖ x d, and since the box moves horizontally, the work done by friction is negative because it is opposite to the direction of motion.