Q4, 5, 8, 10

A box with weight 41 N is on a rough horizontal surface. An external force F is applied horizontally to the box. A normal force and a friction force are also present, denoted by n and f. A force diagram, showing the four forces that act on the box, is shown in the figure. When force F equals 7.4 N, the box is in motion at constant velocity. When force F equals 9.62 N, the acceleration of the box is closest to: O 0.63 m/s2 0.90 m/s2 0.72 m/s2 O 0.81 m/s2 0.53 m/s2How much work must be done by frictional forces in slowing a 1000.0 kg car from 20 m/s to rest? O 2.4 x 105 J O 2.8 x 105 J O 2 x 105 J 1.6 x 105 JA pinball machine compresses a spring 4.0 cm in order to send a 32 g pinball through the machine at 11.0 m/s. What is the spring constant of the spring? 2420 N/m O 0.6 N/m O 242 N/m 1.6 x 10 3 N/mA carriage is pulled through two ropes such that the pulling forces make an angle of 40' as shown in the figure. If both pulling forces have a magnitude of 5.2 N, what third force will cause the object to be in equilibrium? F. O 10.04 N to the right 4.24 N to the right O 11.34 N to the right O 9.77 N to the right O 3.56 N to the right