A boy accelerates a 10 kg wagon from a velocity of 2 m/s to 4 m/s. How much work does the boy do on the wagon?

Oxygen and nutrients are moved through the body by the: a. circulatory system c. lymphatic system b. digestive system d. reproductive system

An open cart is moving along a straight frictionless horizontal track. when rain starts falling vertically into the cart, what happens to the speed of the cart?

I'm thinking it's 2 you are asked to explain the earth's magnetic field. which is the best reply? 1. the earth's magnetic south is similar to the north pole of a magnet. 2. the earth's core has a strong magnetic charge similar to the south pole of a magnet. 3. the earth's geomagnetic south is similar to the south pole of a magnet. 4. the earth's magnetic charge is not centered at either pole; it varies based on location.