An electron with a charge of -1.6 × 10-19 coulombs experiences a field of 1.4 × 105 newtons/coulomb. What is the magnitude of th
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Answer:
C. When an object floats, it does not displace its entire volume.
Explanation:
Buoyancy can be defined as an upward force which is created by the water displaced by an object.
According to Archimede's principle, it is directly proportional to the amount (weight) of water that is being displaced by an object.
Basically, the greater the amount of water an object displaces; the greater is the force of buoyancy pushing the object up. The buoyancy of an object is given by the formula;
Where;
Fb = buoyant force of a liquid acting on an object.
g = acceleration due to gravity.
p = density of the liquid.
v = volume of the liquid displaced.
h = height of liquid (water) displaced by an object.
A = surface area of the floating object.
The unit of measurement for buoyancy is Newton (N).
Additionally, the density of a fluid is directly proportional to the buoyant force acting on it i.e as the density of a liquid decreases, buoyancy decreases and vice-versa.
Furthermore, an object such as a boat, ship, ferry, canoe, etc, are able to float because the volume of water they displace weigh more than their own weight. Thus, if a boat or any physical object weighs more than the volume of water it displaces, it would sink; otherwise, it floats.
In conclusion, the true statement is that when an object floats, it does not displace its entire volume.
Answer:
hinit = 17.5 m
Explanation:
- Assuming no friction present, the mechanical energy must be conserved, which means that at any point of the trajectory, the sum of the gravitational potential energy and the kinetic energy must keep the same.
- At the top of the hill, since it starts from rest, all the energy must be potential, and we can express it as follows:
- When the car arrives to the top of the second hill, as we know that it is lower than the first one, the energy of the car, must be part gravitational potential energy, and part kinetic energy.
- We can express this final energy as follows:
- In order to find hinit, we need to make (1) equal to (2), and solve for it.
- In (2) we have the value of h₂ (10 m), but we still need the value of the speed at the top of the second hill, vf.
- Now, when the car is at the top of the hill, there are two forces acting on it, in opposite directions: the normal force (upward) and the weight (downward).
- We know also that there is a force that keeps the car along the circular track, which is the centripetal force.
- This force is just the net downward force acting on the car (it's vertical at the top), and is just the difference between the weight and the normal force.
- If the cart just barely loses contact with the track at the top of the second hill, this means that at that point the normal force becomes zero.
- So, the centripetal force must be equal to the weight.
- The centripetal force can be expressed as follows:
- We have just said that (3) must be equal to the weight:
- Simplifying, and rearranging, we can solve for vf², as follows:
- Replacing (5) in (2), simplifying and rearranging in (1) and (2) we finally have: