time of 7 seconds, a motorcycle can accelerate from rest to the speed v. Determine the amount of time (in terms of 7) required for it to accelerate from v to 6v if the power output remains constant. At = Determine the speed of the motorcycle (in terms of v) 3T after starting. V f =

4. A car crashes into a tree. What is the work done by the tree stopping the car? The car has a mass of 2075 kg and was traveling at 20.45 m/s. Include a negative if appropriate. Previous submissions:

9) A person in good physical condition can put out 100 W of useful power for several hours at a stretch, perhaps by pedaling a mechanism that drives an electric generator. Neglecting any problems of generator efficiency and practical considerations such as resting time, answer the following.   (a) How many people would it take to run a 3.00 kW electric clothes dryer? _____ people   (b) How many people would it take to replace a large electric power plant that generates 800 MW?  _____people

A playground slide has a height of 4.5m amd is frictionless. A 30 kg child pushes off from the top of the slide so that they have a speed of 5.5 m/s at the fop of Hhe slide. a) What's the child's speed at the bottom of the slide? b) After the bottom of the slide, child skids along a rough patch of ground If the rough patch is 2.2 m the friction an the child when they veach the end of the rough patoh? c) Imagine the playgronnd had a spring (K= 755 N/m) at the end of the patch. If the child were to collide, how muuh wonla they Compress before returning to rest? that has a coefficient of friction Mk= 2.5 long, how mnch work is done by

A person in good physical condition can put out 100 W of useful power for several hours at a stretch, perhaps by pedaling a mechanism that drives an electric generator. Neglecting any problems of generator efficiency and practical considerations such as resting time: (a) How many people would it take to run a 4.00 kW electric clothes dryer? people (b) How many people would it take to replace a large electric power plant that generates 900 MW? people Additional Materials O Reading

A 75 kg sprinter accelerates from 0 to 8.0 m/s in 5.0 s. What is the output power, in kW (kiloWatts)?  Your answer needs to have 2 significant figure, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.