New Tab X PortalGuard - Portal A X Find Value of C X M (no subject) - moebas x Untitled document - C X Content X HW 8 - PHY 251, sect X C webassign.net/web/Student/Assignment-Responses/last?dep=32289191 *LOM Update M Gmail YouTube Courses i Content x Washington, D.C.... 0 Review Trip Detail... All Bookmarks Submit Answer 5. [-/6 Points] DETAILS SERPSE10 8.3.P.008. MY NOTES PRACTICE ANOTHER A 38.5 kg box initially at rest is pushed 5.40 m along a rough, horizontal floor with a constant applied horizontal force of 135 N. If the coefficient of friction between box and floor is 0.300, find the following. a) the work done by the applied force (b) the increase in internal energy in the box-floor system due to friction (c) the work done by the normal force (d) the work done by the gravitational force (e) the change in kinetic energy of the box (f) the final speed of the box m/s Need Help? Read It Submit Answer 6. [-/2 Points] DETAILS SERPSE10 8.4.OP.015.MI. MY NOTES PRACTICE ANOTHER A 195 g block is pressed against a spring of force constant 1.55 kN/m until the block compresses the spring 10.0 cm. The spring rests at the bottom of a ramp inclined at 60.0 to the horizontal. Using energy considerations, determine how far up the incline (in m) the block moves from its initial position be it stops under the following conditions. (a) if the ramp exerts no friction force on the b m (b) if the coefficient of kinetic friction is 0.440 (c) What If? If the ramp is 4.00 m long, what is the maximum coefficient of friction that would allow the block to reach the end of the ramp? Need Help? Read It Master It Submit Answer 7. [-/20 Points] DETAILS SERPSE10 8.4.OP.014.MI.SA. MY NOTES PRACTICE ANOTHER This question has several parts that must be completed sequentially. If you skip a part of the question, you will not receive any points for the skipped part, and you will not be able to come back to the skipped part.New Tab X PortalGuard - Portal A X Find Value of C X M (no subject) - moebas x Untitled document - C x Content X HW 8 - PHY 251, sect X C webassign.net/web/Student/Assignment-Responses/last?dep=32289191 M Update : M Gmail YouTube | Courses il Content x Washington, D.C.... 0 Review Trip Detail... All Bookmarks 8. [-/1 Points] DETAILS SERPSE10 8.5.OP.018. MY NOTES PRACTICE ANOTHER As a sports car travels along a level stretch of road with constant speed, most of the power developed by the engine is used to compensate for the energy transformations due to friction forces exerted on the sports car by the air and the road. If the power developed by the engine is 0.670 hp, calculate the total friction force acting on the sports car (in N) when it is moving at a speed of 26 m/s. One horsepower equals 746 W. IN Need Help? Read it Submit Answer 9. [-/3 Points] DETAILS SERPSE10 8.5.OP.021. MY NOTES PRACTICE ANOTHER A manufacturer uses an elevator to move items from one level to another. The elevator has a mass of 650 kg and moves upward with constant acceleration for 4.00 s until it reaches its cruising speed of 1.75 m/s. (Note: 1 hp = 746 W.) (a) What is the average power (in hp) of the elevator motor during this time interval? Pave hp (b) What is the motor power (in hp) when the elevator moves at its cruising speed? cruising (c) What If? If the elevator motor can only deliver constant power at one setting, the amount needed for its motion at constant speed, how long (in s) will it take the elevator to accelerate to the cruising speed of 1.75 m/s? (If you need to use co or -co, enter INFINITY or -INFINITY, respectively.) t = Need Help? Read It Submit Answer 10. [-/3 Points] DETAILS SERPSE10 8.A.P.031. MY NOTES PRACTICE ANOTHER As the driver steps on the gas pedal, a car of mass 1 140 kg accelerates from rest. During the first few seconds of motion, the car's acceleration increases with time according to the expression below, where t is in seconds and a is in m/s. a = 1.15 t - 0.210 t2 + 0.240 t (a) What is the change in kinetic energy of the car during the interval from t = 0 to t = 2.40 s? (b) What is the minimum average power output of the engine over this time interval? (c) Why is the value in part (b) described as the minimum value? This answer has not been graded yet.New Tab X PortalGuard - Portal A X Find Value of C X M (no subject) - moebas x Untitled document - C x Content X HW 8 - PHY 251, sect X C webassign.net/web/Student/Assignment-Responses/last?dep=32289191 *LOM Update M Gmail YouTube i Courses Content x Washington, D.C.... ( Review Trip Detail... All Bookmarks 11. [-/2 Points] DETAILS SERPSE10 8.A.OP.037. MY NOTES As shown in the figure, a roller-coaster track includes a circular loop of radius R in a vertical plane. A car of mass m is released from rest at a height h above the bottom of the circular section and then moves freely along the track with negligible energy loss due to friction. (a) First suppose the car barely makes it around the loop; at the top of the loop, the riders are upside down and feel weightless. Find the required height h of the release point above the bottom of the loop. (Use any variable or symbol stated above along with the following as necessary: g.) h = (b) If the car is released at some point above the minimum required height, determine the amount by which the normal force on the car at the bottom of the loop exceeds the normal force on the car at the top of the loop. (Consider the moments when the car reaches the top and when it reaches the bottom again. Use any variable or symbol stated above along with the following as necessary: g.) NB - NT= The normal force on each rider follows the same rule. Such a large normal force is dangerous and very uncomfortable for the riders. Roller coasters are therefore not built with circular loops in vertical planes. The photograph shows an actual design. Need Help? Read It Submit Answer 12. [-/2 Points] DETAILS SERPSE10 8.A.OP.032.MI. MY NOTES PRACTICE ANOTHER A block of mass m, = 16.0 kg is connected to a block of mass my = 32.0 kg by a massless string that passes over a light, frictionless pulley. The 32.0-kg block is connected to a spring that has negligible mass and a force constant of k = 220 N/m as shown in the figure below. The spring is unstretched when the system is as shown in the figure, and the incline is frictionless. The 16.0-kg block is pulled a distance h = 18.0 cm down the incline of angle 0 = 40.0 and released from rest. Find the speed of each block when the spring is again unstretched