A 100 N crate is being pushed across a level floor at a constant speed by a force F = 300 N at an angle of 20.0° below the horizontal, as shown in the figure below. What is the coefficient of kinetic friction between the crate and the floor?

As part of your daily workout, you lie on your back and push with your feet against a platform attached to two stiff springs arranged side by side so that they are parallel to each other. when you push the platform, you compress the springs. you do an amount of work of 79.0 j when you compress the springs a distance of 0.230 m from their uncompressed length. (a) what magnitude of force must you apply to hold the platform in this position? (b)how much additional work must you do to move the platform a distance 0.230 m farther? (c) what maximum force must you apply to move the platform a distance 0.230 m farther?

First answer marked as brainiest which is the correct equation describing the first law of thermodynamics? a) when the internal energy of a system changes, it equals the amount of heat added plus the work done. b) when work is done by the piston, it is equal to the heat added plus the change in internal energy of the system. c) when heat is added to the system, it is equal to the amount of work done by the piston plus the change in internal energy of the system.

Aman is trying to drag a small tree that he cut down. if the static coefficient of friction of the tree on the ground is 0.5 and the tree weighs 670 n, what is the minimum amount of horizontal force that the man will need to apply so that the tree will start moving? o a. 465 n o b. 230 n o c. 670 n o d. 335 n