When a person stands on tiptoe (a strenuous position), the position of the foot is as shown in Figure a. The total gravitational force on the body, Fe, is supported by the force n exerted by the floor on the toes of one foot. A mechanical model of the situation is shown in Figure b, where T is the force exerted by the Achilles tendon on the foot and R is the force exerted by the tibia on the foot. Find the values of T, R, and 0 when F, = n = 720 N. (For 0, enter the smaller of the two possible values between 0° and 90°.)

A 2.0-m-long rod has a density in kilograms per meter A = a + bx ,where a = 1.0 kg/m, b = 1.0 k9/m², and x is the distance from the left end of the rod. The rod rests horizontally with each end supported by a scale. The force exerted by the left scales is 39.2 N 22.9 N 16.3 N 4.0 N 32.6 N

Directions: Assume, unless otherwise specified, that all numbers have at least 3 significant figures. F (N) Students collect data, see graph, for the force involved in stretching a rubber band. The data is well fit by the equation F = 33.65 x0.4971, 12 10 where F is in newtons and x is in meters. One end of the rubber band is attached to a stationary vertical rod and the other end to a 0.3 kg mass. The mass rests on a frictionless horizontal surface. The mass is pulled back such that the rubber band is stretched by 0.8 m from its unstretched length and then released from rest. 4. x (m) 0,1 0.02 0.04 0.06 0.08 A. What is the speed of the mass after it has traveled 0.4 m? B. What is the maximum speed of the object?

When a person stands on tiptoe (a strenuous position), the position of the foot is as shown in Figure a. The total gravitational force on the body, F, is supported by the force n exerted by the floor on the toes of one foot. A mechanical model of the situation is shown in Figure b, where T is the force exerted by the Achilles tendon on the foot and R is the force exerted by the tibia on the foot. Find the values of T, R, and e when F, = n = 675 N. (For e, enter the smaller of the two possible values between 0° and 90°.) Achilles tendon Tibia 15.0° 18.0 cm 25.0 cm T = N R = N Need Help? Read It

A 20 kg dog stands on a 40 kg platform that is supported by two ropes. One rope is attached to the right edge of the platform and the other is attached 50 cm from the left edge of the platform. The dog sits 50 cm from the right edge of the platform. A 5.0 kg cat jumps up, but is wary of the dog abs stays all the way on the left edge. The platform is 2.0 m long. What is the tension in each rope?

Two children push on opposite sides of a door during play. Both push horizontally and perpendicular to the door. One child pushes with a force of 185 N at a distance of 0.600 m from the hinges, and the second pushes at a distance of 0.400 m. What force (in N) must the second exert to keep the door from moving? Assume friction is negligible.

One end of a uniform 4.10-m-long rod of weight Fg is supported by a cable at an angle of ? = 37° with the rod. The other end rests against the wall, where it is held by friction as shown in the figure below. The coefficient of static friction between the wall and the rod is ?s = 0.480. Determine the minimum distance x from point A at which an additional object, also with the same weight Fg, can be hung without causing the rod to slip at point A. ------m

Item 9 A garage door is mounted on an overhead rail (Figure 1). The wheels at A and B have rusted so that they do not roll, but rather slide along the track. The coefficient of kinetic friction is 0.54. The distance between the wheels is 2.00 m, and each is 0.50 m from the vertical sides of the door. The door is uniform and weighs 900 N. It is pushed to the left at constant speed by a horizontal force F, that is applied as shown in the figure. Figure B k A K 2.00 m -3.00 m h F 1 of 1 If the distance his 1.60 m, what is the vertical component of the force exerted on the wheel A by the track? Express your answer to two significant figures and include the appropriate units. μA ? nA = Value Units Submit Previous Answers Request Answer X Incorrect; Try Again; 4 attempts remaining Part B If the distance h is 1.60 m, what is the vertical component of the force exerted on the wheel B by the track? Express your answer with the appropriate units. μÅ ? nB = Value Units Submit Request Answer Part…

+ A uniform ladder stands on a rough floor and rests against a frictionless wall as shown in the figure. Since the floor is rough, it exerts both a normal force N, and a frictional forcef, on the ladder. However, since the wall is frictionless, it exerts only a normal force N₂ on the ladder. The ladder has a length of L = 4.2 m, a weight of W, = 66.5 N, and rests against the wall a distance d = 3.75 m above the floor. If a person with a mass of m= 90 kg is standing on the ladder, determine the following. (a) the forces exerted on the ladder when the person is halfway up the ladder (Enter the magnitude only.) N₂ N₂- 4- (b) the forces exerted on the ladder when the person is three-fourths of the way up the ladder (Enter the magnitude only.) N₂ N₂ Additional Materials

To run Slap-chop and use Sham-wow you need to be in shape. For a work out, the man in the figure uses a device consisting of four springs arranged as shown. Each spring has a spring constant of 75.5 N/m. The hands holding the unstretched device are 36.34 cm apart. If the person can extend the springs to 61.87 cm apart, what is the maximum lateral force exerted by each hand?