2. [3.33/6.66 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016ACC 5.1.P.018. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A contestant in a winter games event pushes a 33.0 kg block of ice across a frozen lake as shown in the figure below. 25 The coefficient of static friction is 0.1 and the coefficient of kinetic friction is 0.03. (For each answer, enter a number.) (a) Calculate the minimum force F (in N) he must exert to get the block moving. 37.4 N (b) What is its acceleration (in m/s ) once it starts to move, if that force is maintained? 0.7 x m/s24. [0/6.66 Points] DETAILS PREVIOUS ANSWERS OSCOLPHYS2016ACC 6.1.P.001. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Semi-trailer trucks have an odometer on one hub of a trailer wheel. The hub is weighted so that it does not rotate, but it contains gears to count the number of wheel revolutions-it then calculates the distance traveled. If the wheel has a 1.17 m diameter and goes through 220,000 rotations, how many kilometers should the odometer read? (Enter a number.) 1617.3 X km + Submit Answer1. [-/5.71 Points] DETAILS OSCOLPHYS2016ACC 7.1.P.001. MY NOTES ASK YOUR TEACHER PRACTIC How much work does a supermarket checkout attendant do on a can of soup he pushes 0.770 m horizontally with a force of 4.20 N? Express your answer in joules and kilocalories. (For each answer, enter a number.) work in joules work in kilocalories kcal Submit Answer 2. [-/5.71 Points] DETAILS OSCOLPHYS2016ACC 7.1.P.006. MY NOTES ASK YOUR TEACHER PRACTIC How much work (in ]) is done by the boy pulling his sister 36 m in a wagon as shown in the figure below? F 30 d O O Assume no friction acts on the wagon. (Assumed = 36 m and F = 49 N. Enter a number.) W =3. [45.71 Points] DSCOLPHVSZMGACC 7.1.P.004. l MV NOTES l l ASK YOUR TEACHER | PRACTICE ANOTHER Suppose a car travels 105 km at a speed of 30.0 m/s, and uses 1 80 gallons of gasoline. Only 30% of the gasoline goes into useful work by the force that keeps the car moving at constant speed despite Friction. (The energy content of gasoline is 1.30 x 103] per gallon.) (a) What is the Force (in N) exerted to keep the car moving at constant speed? (Enter a number.) N (b) If the required force is directly proportional to speed, how many gallons Will be used to drive 108 km at a speed of 28.0 m/s? (Enter a number.) gallons SubmilAnswel 4. [45.71 Points] DSCOLPHVSZMGACC 7.2.P.015. MV NOTES H ASK YOUR TEACHER I PRACTICE ANOTHER Using energy considerations, calculate the average Force (in N) a 65.0 kg sprinter exerts backward on the track to accelerate From 2.00 to 7.00 m/s in a distance of 25.0 m, if he encounters a headwmd that exerts an average force of 30.0 N against him. (Enter a number.) N SubmilAnswer 5. [45.71 Points] OSCOLPHYSZMGACC 7.2.P.013. MV NOTES ASK YOUR TEACHER PRACTICE ANOTHER A car's bumper is designed to withstand a 5.76 km/h (1.6 m/s) collision With an immovable object without damage to the body of the car. The bumper cushions the shock by absorbing the force over a distance. Calculate the magnitude of the average force (in N) on a bumper that collapses D 195 m while bringing a 890 kg car to rest from an initial speed of 1.6 m/s. (Enter a number.) N 6. [15.71 Points] DETAILS OSCOLPHVSZMGACC 7.3.P.0'l7. MY NOTES I I ASK YOUR TEACHER l | PRACTICE ANOTHER (a) How much gravitationai potential energy (in J) (relative to the ground on Whit is built) is stored in an Egyptian pyramid, given its mass is about 7 x 109 kg and its Center of mass is 30.0 m above the surrounding ground? (Enter a number.) :1 (b) What is the ratio of this energy to the daiiy food intake of a person (1.2 x 107 1)? (Enter your answer as a ratio to the number 1. Enter a number.) :1 Sub mil Answer 7. [-15.74 Points] OSCOLPHVSZO16ACC 7.3.F.016. ASK YOUR TEACHER PRACTICE ANOTHER (a) What is the gravitational potentiai energy (in J) relative to the generators of a lake of volume 43.0 km3 (mass : 4.30 x 1013 kg), given that the lake has an average height of 39.0 m above the generators? :1 A hydroelectric power facility converts the gravitational potential energy of water behind a dam to electric energy. (For each answer, enter a number.) (in) Compare this With the energy stored in a Qimegaton fusion bomb. Elake/Ebomb : : Sub mil