Question

#2

1. A block of wood has a mass of 25 kg and a density of 650 kg/m'. You are holding it under water by pushing downward. a) What is the volume of the block of wood? b) What is the buoyant force on it? c) What is the magnitude of the downward force you are exerting to hold the block under water? 2. In the diagram, the hinge is frictionless and the system is in equilibrium. The uniform beam is 4 meters long and has a mass of 150 kg. The mass hanging from the end of the beam is 175 kg. The beam wire is attached I m from the end. Calculate a) the tension in the beam wire b) the horizontal and vertical components of the force exerted by the hinge on the beam. beam wire 175kg O Chinge 3. A concrete cube, 0.5 meters on each side, is lowered beneath the surface of Seneca Lake. At what depth is the water around it exerting an inward force of 1.7x10 newtons on each face of the cube? in attached to a snrine and ascillates on a horizontal frictionless surface in the

Answer 1

1. Volume of block of wood = ? FB ( Buoyent forced 7 wote (8-10 18/ mass of wood cm) Density of wood C Swabd) Volume of wood I woad = m I i & force Exert by us by Holding V = m Swood = 25 m3 ng = 25x9.8 = 2454 650 -3 m3) & IV = 38.5 X lo mol Buoyant Force = ? I (FB) FR = /volume of lr Density a wood Blocke) liquid = V Swater g where Swath = 10 kg/m = (38.5x103) (109)(9:8) 1FB = 377.301 (C) CO f force Exert ! is to hold wood shoclo in wote for Equilibrium of block in water FB = f t mg Ving F = Fg-mg = 377.3 - 25x9.8 = 877•3 - 245 = 132.3 Newton F = 132.3N