Answer :
The frictional force on the block from the floor and the block's acceleration are 10.45 N and 0.73 m/s².
Explanation :
Given that,
Mass of block = 3.50
Angle = 30°
Force = 15.0 N
Coefficient of kinetic friction = 0.250
We need to calculate the frictional force
Using formula of frictional force
(II). We need to calculate the block's acceleration
Using newton's second law of motion
Hence, The frictional force on the block from the floor and the block's acceleration are 10.45 N and 0.73 m/s².
Answer:
The correct statement is "The electric field is directed toward the electron and has a magnitude of 
".
Explanation:
According to Coulomb's law, the magnitude of the electric field due to a static point charge q at a point r distance away from it is given by
- k is the Coulmob's constant.
The direction of the electric field along the line joining the charge and the point where electric field is to be found and it is directed from positive charge to negative charge.
Conventionally, we assume a positive test charge placed at the point where electric field is to be found, the test charge has very small charge such that its charge does not affect the electric field due to the given charge.
The charge on the electron = -e.
The electric field due to an electron is given by
The direction of this electric field is from positive test charge, placed at the point where electric field is to be found, towards the electron along the line joining the two.
Thus, the correct statement is "The electric field is directed toward the electron and has a magnitude of ".
Answer: apparent weighlessness.
Explanation:
1) Balance of forces on a person falling:
i) To answer this question we will deal with the assumption of non-drag force (abscence of air).
ii) When a person is dropped, and there is not air resistance, the only force acting on the person's body is the Earth's gravitational attraction (downward), which is the responsible for the gravitational acceleration (around 9.8 m/s²).
iii) Under that sceneraio, there is not normal force acting on the person (the normal force is the force that the floor or a chair exerts on a body to balance the gravitational force when the body is on it).
2) This is, the person does not feel a pressure upward, which is he/she does not feel the weight: freefalling is a situation of apparent weigthlessness.
3) True weightlessness is when the object is in a place where there exists not grativational acceleration: for example a point between two planes where the grativational forces are equal in magnitude but opposing in direction and so they cancel each other.
Therefore, you conclude that, assuming no air resistance, a person in this ride experiencing apparent weightlessness.
Answer: 7.41 m/s
Explanation: By using the law of of energy, kinetic energy of the brick as it falls equals the potential energy before falling.
Kinetic energy = mv²/2, potential energy = mgh
mv²/2 = mgh
v²/2 = gh
v² = 2gh
v = √2gh
Where g = 9.8 m/s², h = 2.80m
v = √2×9.8×2.8 = 7.41 m/s
