What is the work done by friction when a 5 kg block slides 2 m on a surface with
Practice Questions
Q1
What is the work done by friction when a 5 kg block slides 2 m on a surface with a coefficient of kinetic friction of 0.4?
-4 N·m
-8 N·m
-10 N·m
-20 N·m
Questions & Step-by-Step Solutions
What is the work done by friction when a 5 kg block slides 2 m on a surface with a coefficient of kinetic friction of 0.4?
Step 1: Identify the mass of the block. The mass is 5 kg.
Step 2: Identify the distance the block slides. The distance is 2 m.
Step 3: Identify the coefficient of kinetic friction (μk). The coefficient is 0.4.
Step 4: Calculate the normal force (N). The normal force for a flat surface is equal to the weight of the block, which is mass times gravity: N = mass * gravity = 5 kg * 9.8 m/s².
Step 5: Calculate the normal force: N = 5 kg * 9.8 m/s² = 49 N.
Step 6: Calculate the frictional force (F_friction) using the formula: F_friction = μk * N.
Step 7: Substitute the values: F_friction = 0.4 * 49 N = 19.6 N.
Step 8: Calculate the work done by friction using the formula: Work = -F_friction * distance.
Step 9: Substitute the values: Work = -19.6 N * 2 m = -39.2 N·m.
Step 10: Round the answer if necessary. The work done by friction is approximately -40 N·m.
