The speed of the pendulum at point 3 is 1.4 m/s
Explanation:
We can solve this problem by using the law of conservation of energy. In fact, the mechanical energy of the pendulum (which is the sum of his potential energy + his kinetic energy) must be conserved. So we can write:
where
is the initial potential energy, at the highest position
is the initial kinetic energy, at the highest position
is the final potential energy, at the lowest position
is the final kinetic energy, at the lowest position
We are told that:
is the potential energy of the pendulum at the maximum height
(when the pendulum is at maximum height, the speed is zero, so the kinetic energy is zero)
(potential energy is zero at the lowest position)
Therefore,
Kinetic energy can be rewritten as
where
m = 10 kg is the mass of the pendulum
v is its speed at point 3
Solving for v,
Learn more about kinetic energy:
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The energy the electron gives up passing between the electrodes is equal to the product between its charge and the potential difference between the electrodes:
where
e is the electron charge
is the potential difference
Plugging numbers into the equation, we find that the electron gives up is
Answer:
PE = 3.92x10^16J
potential energy
Explanation:
PE = m*g*h
mass of water = 1000kg/m³
(4*10^10m³)*1000kg = 4*10^13kg
PE = (4*10^13kg)*(9.81m/s²)*(100m)
PE = 3.92x10^16J
The first: alright, first: you draw the person in the elevator, then draw a red arrow, pointing downwards, beginning from his center of mass. This arrow is representing the gravitational force, Fg.
You can always calculate this right away, if you know his mass, by multiplying his weight in kg by the gravitational constant
let's do it for this case:
the unit of your fg will be in Newton [N]
so, first step solved, Fg is 637.65N
Fg is a field force by the way, and at the same time, the elevator is pushing up on him with 637.65N, so you draw another arrow pointing upwards, ending at the tip of the downwards arrow.
now let's calculate the force of the elevator
so you draw another arrow which is pointing downwards on him, because the elevator is accelating him upwards, making him heavier
the elevator force in this case is a contact force, because it only comes to existence while the two are touching, while Fg is the same everywhere
The correct answer to the question is 130.4 N.
CALCULATION;
The mass of the bullet is given as m = 28 gram = 0. 028 kg.
The initial velocity of the bullet u = 55 m/s
The final velocity of the bullet v = 18 m/s.
The distance covered by the bullet through the sand bag s = 29 cm.
= 0.29 m
Let the acceleration of the bullet is a .
From equation of kinematics, we know that-
⇒ 
The negative sign is used due to the fact that force is opposing in nature. Its velocity is decreasing with time.
From Newton's second law of motion, we know that net force on a body is equal to the product of mass with acceleration.
Mathematically F = ma.
Hence, the frictional force exerted on the bullet is calculated as -
F = m × a
= 0.028 × (-4656.897) N
= -130.4 N [ANS]
Here, N ( newton) stands for the unit of force.
