A mother pulls her two children on a sled through the snow along a flat street. How much work is done if she pulls her children 100 feet with a constant force of 40 pounds at an angle of 28°?

Fx * x = 40 cos 28 * 100 foot pounds

To calculate the work done, we need to use the formula:

Work = Force * Distance * cos(angle)

Here, the force is given as 40 pounds and the distance is given as 100 feet. However, since the force is applied at an angle, we need to consider the angle in calculating the work done. The angle given is 28°.

First, we need to convert the force from pounds to newtons. 1 pound is approximately equal to 4.44822 newtons. Therefore, 40 pounds would be 40 * 4.44822 = 177.929 newtons.

Next, we need to convert the angle from degrees to radians. To convert degrees to radians, you can use the formula: radians = (degrees * π) / 180. So, first convert 28 degrees to radians:

28° * π / 180 = 0.4887 radians (approx.)

Now we can calculate the work done using the formula:

Work = 177.929 newtons * 100 feet * cos(0.4887 radians)

To calculate the cosine of 0.4887 radians, you can use a scientific calculator or a calculator with a cosine function. The cosine value should be approximately 0.882

Work = 177.929 newtons * 100 feet * 0.882

Finally, multiply the values:

Work ≈ 15677.1 joules (to the appropriate number of significant figures)

Therefore, the work done by the mother pulling her children on the sled is approximately 15677.1 joules.