A boulder in a river has weight of 65N. It displaces a volume of water with a weight of 10N. Which is the net force on this rock?
55 N down
65 N down
75 N up
75 N down
Fn = 65 - 10 = 55 N, Downward.
f
To determine the net force on an object, we need to consider the forces acting on it. In this case, there are two forces acting on the boulder: gravity and buoyancy.
The force of gravity acts downward and has a magnitude equal to the weight of the boulder, which is given as 65N. This force is always directed vertically downward.
The force of buoyancy acts upward and has a magnitude equal to the weight of the displaced water. In this case, the displaced water has a weight of 10N, so the force of buoyancy is 10N directed vertically upward.
To find the net force, we need to subtract the force of buoyancy from the force of gravity.
Net force = Force of gravity - Force of buoyancy
Net force = 65N - 10N
Net force = 55N
Therefore, the net force on the boulder is 55N downward. So, the correct answer is: 55 N down.