The diagram below shows the plan view of a door hinged at A. If a man applies a force, F, of 40 N at the end marked B, calculate the
moment of this force about A. What is the minimum force X that must
be applied at C in order to stop the door from turning? Name the
principle applied to solve this problem.
'1.8 m
B
A
1.2 m

An object's buoyant force and weight mean the same thing. a. trueb. false

Aball with a mass of 275 g is dropped from rest, hits the floor and rebounds upward. if the ball hits the floor with a speed of 2.40 m/s and rebounds with a speed of 1.70 m/s, determine the following. (a) magnitude of the change in the ball's momentum (let up be in the positive direction.)

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.