Work energy-hwk

Work and Kinetic Energy Homework Problems 1. An intern pushes a 72 kg patient on a 15 kg gurney, producing an acceleration of 0.60 a. How much work does the intern do by pushing the patient and the gurney through a distance of 2.5 m? Assumed the gurney moves without friction b. How far must the intern push the gurney to do 140 J of work? 2. One species of Darwins finch, Geospiza magnirostris, can exert a force of 205 N with its beak as it cracks open a Tribulus seed case. If its beak moves through a distance of 0.40 cm during this operation, how much work does the finch do to get the seed? 3. In a gravity escape system (GES), an enclosed lifeboat on a large ship is deployed by letting it slide down a ramp and then continuing in free fall to the water below. Suppose a 4970 kg lifeboat slides a distance of 5.00 m on a ramp, dropping though a vertical height of 2.50 m. How much work does gravity do on the boat? 4. you want to load a box into the back of a truck. One way is to lift it straight up through a height h, as shown, doing a work W1. Alternatively, you can slide a box up a loading ramp a distance L, doing work W2. Assuming the box slides on the ramp without friction, which of the following is correct 5. A car of mass m coasts down a hill inclined at an angle ø below the horizontal. The a. the normal force N exerted by the roadb. a force due to air resistance Fairc. The force of gravity mg i. Find the total work done on the car as it travels a distance d along the road 6. Consider the previous example- calculate the total work done on the car using 7. A truck moving at 15 m/s has a kinetic energy of 4.2 E 5 J a. What is the mass of the truckb. By what multiplicative factor does the kinetic energy of the truck increase if its 8. How much work is required for a 74 kg sprinter to accelerate from rest to 2.2 m/s9. A 4.10- kg box of books is lifted vertically from rest a distance of 1.60 m with a constant, upward applied force of 52.7 N. Find a. the work done by the applied forceb. the work done by gravityc. the final speed of the box 10. A boy exerts a force of 11.0 N at 29˚ above the horizontal on a 6.40 kg sled find a. the work done by the boyb. the final speed of the sled after it moves 2.00 m, assuming the sled starts with an initial speed of 0.500 m/s and slides horizontally without friction 11.To accelerate a certain car from rest to the speed v requires the work W1. The work needed to accelerate the car from v to 2v is W2. Which of the following is correct 12.The spring in a pinball launcher has a force constant of 405 N/m. How much work is required to compress the spring a distance of 3.00 cm 13.The work required to deflect a typical AFM cantilever by 0.10 nm is 1.2 E -20 J a. What is the force constant of the cantilever treating it as an ideal springb. How much work is required to increase the deflection of the cantilever from 0.10 14.Suppose the block which is connected to a spring horizontally has a mass of 1.5 kg and moves with an initial speed of v0= 2.2 m/s. Find the compression of the spring, whose force constant is 475 N/m, when the block momentarily comes to rest 15.To pass a slow moving truck, you want your fancy 1.30 E3 kg car to accelerate from 13.4 m/s to 17.9 m/s in 3.00 s. What is the minimum power required for this pass? 16.It takes a force of 1280 N to keep a 1500 kg car moving with constant speed up a slope of 5.00˚. If the engine delivers 50.0 hp to the drive wheels, what is the maximum speed of the car

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