A spring with k = 15 N/m with equilibrium length 30 cm is attached vertically to a surface and then allowed to come to equilibrium, after which a weight with mass 0.2 kg is attached to the top side of the spring. → How much work does the spring do on the weight via the elastic force between its initial position and the new equilibrium height? (Use integral) |

Two constant forces F1 = 5 ^i +4.7 j+7.3^ k N and F2 = 3.6^i -4.4 j-2.3^k N act together on an object causes a displacement from position r1 = 3.7^i+ 4 j+8.9° k cm to position r2= 9.1°i + 2.1 `j+ 5.7^k cm. Determine the total work done (J) on the object. Answer:

A 51-kg box is being pushed a distance of 7.0 m across the floor by a force P→⁢ whose magnitude is 185 N. The force P→⁢ is parallel to the displacement of the box. The coefficient of kinetic friction is 0.21. Determine the work done on the box by each of the four forces that act on the box. Be sure to include the proper plus or minus sign for the work done by each force.

Consider a hanging spring of negligible mass that does not obey Hooke's law. When the spring is pulled downward by a distance x, the spring exerts an upward force of magnitude αlpha(x^2), where α is a positive constant. Initially, the hanging spring is relaxed (not extended). We then attach a block of mass m to the spring and release the block Calculate the work done on the block by the spring as the block falls an arbitrary distance x Calculate the work done on the block by any other forces as the block falls an arbitrary distance x Find the xx-component of the net force that acts on the block when it is at x_2.

16-2. A block of mass 2.56 kg is pushed 2.00 m along a frictionless horizontal table by a constant16.5 N force directed 25.3◦ below the horizontal. Determine the work done by (a) theapplied force, (b) the normal force exerted by the table, (c) the force of gravity, and (d) thenet force on the block.Brainstorm ideas that will help you solve this problem(a) Determine the work done by the applied force.(b) Determine the work done by the normal force exerted by the table.(c) Determine the work done by the force of gravity.(d) Determine the work done by the net force on the block.       my understanding is that work is equal to force times displacment. I figured that a) is 33 j and since b) and c) the object doesn't move up or down it is 0. However I am not certain. Please help!

1. A 23.0 kg child is playing on a swing with a length of 2.5 m. If the swing starts from rest and makes an angle of 40.0◦ with the vertical at the top of the swing, a) determine the child’s speed at the bottom of the swing neglecting friction. b) If the swing has a speed of 2.8 m/s at the bottom, determine the work done by friction during the downswing and, bonus) assuming the force of friction is constant, determine the maximum angle the swing attains on the upswing after passing through the bottom. Hint: Use the approximation that cos θ ≈ 1 − 1 2 θ 2 for angles given in radians.