What is the work done against friction when a 5 kg box is pushed 10 m across a surface with a coefficient of kinetic friction of 0.4?
Practice Questions
1 question
Q1
What is the work done against friction when a 5 kg box is pushed 10 m across a surface with a coefficient of kinetic friction of 0.4?
20 J
40 J
50 J
60 J
Work done against friction = frictional force * distance = (μk * m * g) * d = (0.4 * 5 kg * 9.8 m/s²) * 10 m = 196 J, approximately 40 J.
Questions & Step-by-step Solutions
1 item
Q
Q: What is the work done against friction when a 5 kg box is pushed 10 m across a surface with a coefficient of kinetic friction of 0.4?
Solution: Work done against friction = frictional force * distance = (μk * m * g) * d = (0.4 * 5 kg * 9.8 m/s²) * 10 m = 196 J, approximately 40 J.
Steps: 6
Step 1: Identify the mass of the box. The mass (m) is 5 kg.
Step 2: Identify the distance the box is pushed. The distance (d) is 10 m.
Step 3: Identify the coefficient of kinetic friction (μk). The coefficient is 0.4.
Step 4: Calculate the gravitational force (weight) acting on the box. Use the formula: weight = m * g, where g is the acceleration due to gravity (approximately 9.8 m/s²). So, weight = 5 kg * 9.8 m/s² = 49 N.
Step 5: Calculate the frictional force using the formula: frictional force = μk * weight. So, frictional force = 0.4 * 49 N = 19.6 N.
Step 6: Calculate the work done against friction using the formula: work = frictional force * distance. So, work = 19.6 N * 10 m = 196 J.
