Question

A block of mass 15.0 kg slides down a ramp inclined at 28.0∘ above the horizontal. As it slides, a kinetic friction force of 30.0 N parallel to the ramp acts on it. If the block slides for 7.50 m along the ramp, Find the work done on the block by friction.

Answer 1

The work done on the block by friction is calculated using the formula Work = Force × Distance × cos(θ), resulting in -225.0 Joules. The negative sign represents the work done against the motion of the block.

Step-by-step explanation:

To find the work done on the block by friction, we need to use the formula for work which is:

Work = Force × Distance × cos(θ)

Where the force is the friction force, the distance is the distance the block slides, and θ is the angle between the force and the direction of the motion. For kinetic friction, this angle is 180° because the friction force acts in the opposite direction to the block's motion.

Let's plug in the values:

• Force of friction (Φ) = 30.0 N
• Distance (d) = 7.50 m
• θ = 180° because friction acts opposite to motion

Work done by friction (W) = 30.0 N × 7.50 m × cos(180°)

Cosine of 180° is -1, so:

W = 30.0 N × 7.50 m × -1

W = -225.0 J

The negative sign indicates the work done by the friction force acts to reduce the kinetic energy of the block.