Suppose a child pulls on the rope of a sled with a force of 75N and at an angle of 20° with the ground. If the sled moves 40 m along the surface of the ground, how much work was done?

1 answer

To calculate the work done on the sled by the child, we can use the formula for work, which is given by:

\[ W = F \cdot d \cdot \cos(\theta) \]

Where:

  • \( W \) is the work done,
  • \( F \) is the force applied,
  • \( d \) is the distance moved in the direction of the force,
  • \( \theta \) is the angle between the force and the direction of motion.

In this case:

  • \( F = 75 , \text{N} \)
  • \( d = 40 , \text{m} \)
  • \( \theta = 20^\circ \)

First, we need to find \( \cos(20^\circ) \):

\[ \cos(20^\circ) \approx 0.9397 \]

Now we can substitute these values into the work formula:

\[ W = 75 , \text{N} \cdot 40 , \text{m} \cdot \cos(20^\circ) \]

Calculating this:

\[ W = 75 \cdot 40 \cdot 0.9397 \] \[ W = 3000 \cdot 0.9397 \] \[ W \approx 2819.1 , \text{J} \]

Therefore, the work done by the child on the sled is approximately 2819.1 Joules.