9. an 800 kg police boat slows down uniformly from 50 km/h [e] to 20 km/h (e) as it enters a
harbour. if the boat slows down over a 30 m distance, what is the force of friction on the boat?
(hint: you will need to convert the velocities into m/s.)

Identify the type of synthetic material used in each object

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

Ahanging spring stretches by 35.0 cm when an object of mass 450 g is hung on it at rest. in this situation, we define its position as x = 0. the object is pulled down an additional 18.0 cm and released from rest to oscillate without friction. what is its position x at a moment 84.4 s later? express your answer in cm.