A variable force F is applied to a block, and the relationsh…

A variable force F is applied to a block, and the relationship between the force and the block’s displacement is shown in the figure. x1 = m, x2 = m, x3= 30 m, F1= N, F2= 30 N, and F3= N. The positive directions of the force and displacement are the same (toward right). Calculate the work done by the force as the block moves from position x1 to position x2. Express your answer in joules (J). 

A [m] kg box is moving on a horizontal surface in the +x dir…

A kg box is moving on a horizontal surface in the +x direction (toward the right). The coefficient of kinetic friction is . An unknown force F, parallel to the surface, is applied to the box. The velocity as a function of time is shown in the figure. Given t1 = s, t2 = s, v1 = m/s, and v3 = m/s, determine the magnitude of the force F during the time interval from t1 to t2. Express your answer in newtons.