Answer:
d. Both A & C
Explanation:
- The velocity of the ball is a vector, whose magnitude indicates its rate of change of position, and it has a direction. In this case, the ball is moving upward, therefore the direction of motion is upward, so the direction of the velocity is upward as well.
- The acceleration of the ball is a vector, whose magnitude indicates the rate of change of the velocity. The direction of the acceleration is:
-- positive if the the magnitude of the velocity is increasing
-- negative if the magnitude of the velocity is decreasing
For a ball thrown upward, the acceleration is given by the acceleration of gravity,
. This acceleration points downward, and it is constant during the entire motion. In particular, it does not change direction, as it is always directed downward. Therefore, the acceleration of the ball is downward.
So, the correct answer is
d.Both A & C
Since A and C are both true:
a.The velocity vector is directed upward.
c.The acceleration is directed downward.
Explanation:
The ratio of the areas is the square of the ratio of the radii.
A/A = 3.16² = 9.99
The ratio of the volumes is the cube of the ratio of the radii.
V/V = 3.16³ = 31.6
Given that,
Voltage = 10 volt
Suppose, The three resistance is connected in parallel and each resistance is 12 Ω. find the current in the electric circuit.
We need to calculate the equivalent resistance
Using formula of parallel

Put the value into the formula



We need to calculate the current in the circuit
Using ohm's law


Where, V = voltage
R = resistance
Put the value into the formula


Hence, The current in the circuit is 2.5 A
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
Operant conditioning, sometimes called <em>instrumental learning</em>, was first extensively studied by Edward L. Thorndike, who observed the behavior of cats trying to escape from home-made puzzle boxes.
Hope this helps!