# Question

A certain amount of work W is required to accelerate a car from rest to a speed v. If instead an amount of work equal to 2Wis done on the car, what is the carâ€™s speed?

## Answer to relevant Questions

Car B is traveling twice as fast as car A, but car A has four times the mass of car B. Which car has the greater kinetic energy? (a) Does efficiency describe how fast work is done? Explain. (b) Does a more powerful machine always per-form more work than a less powerful one? Explain. If a person does 50 J of work in moving a 30-kg box over a 10-m distance on a horizontal surface, what is the minimum force required? To measure the spring constant of a certain spring, a student applies a 4.0-N force, and the spring stretches by 5.0 cm. What is the spring constant? A particular spring has a force constant of 2.5 x 103 N/m. (a) How much work is done in stretching the relaxed spring by 6.0 cm? (b) How much more work is done in stretching the spring an additional 2.0 cm?Post your question

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