Superman stops a "speeding locomotive" of mass 8.0x103 kg in 4.0 seconds. If the train was originally moving at 40.m/s, a) what is the change in momentum?

b.) What is the magnitude of the force which Superman exerts on the train?

When using the scientist method, which step comes last?

Choose the correct general statement concerning the total potential and kinetic energy at any point along the arc of swing. the total energy at any point along the arc of swing of the pendulum is always less than 12 joules. the total energy at any point along the arc of swing of the pendulum is always more than 12 joules. the total energy at any point along the arc of swing of the pendulum is always equal to 12 joules. not enough information to determine

Mrs. smith does her daily chores. she walks 5 m to the laundry room and then turns around and walks -14 m to the kitchen. the whole process takes her 11 minutes. what was her average velocity for these events? (choose more than 1) a. 1.48 m/s b. 0.212 m/s c. -0.136 m/s d. -0.0075 m/s