Answer:
D. When the box is placed in an elevator accelerating upward
Explanation:
Looking at the answer choices, we know that we want to find out how the normal force varies with the motion of the box. In all cases listed in the answer choices, there are two forces acting on the box: the normal force and the force of gravity. These two act in opposite directions: the normal force, N, in the upward direction and gravity, mg, in the downward direction. Taking the upward direction to be positive, we can express the net force on the box as N - mg.
From Newton's Second Law, this is also equal to ma, where a is the acceleration of the box (again with the upward direction being positive). For answer choices (A) and (B), the net acceleration of the box is zero, so N = mg. We can see how the acceleration of the elevator (and, hence, of the box) affects the normal force. The larger the acceleration (in the positive, i.e., upward, direction), the larger the normal force is to preserve the equality: N - mg = ma, N = ma+ mg. Answer choice (D), in which the elevator is accelerating upward, results in the greatest normal force, since in that case the magnitude of the normal force is greater than gravity by the amount ma.
Answer:
<em>The vertical acceleration is -9.81 m/s^2</em>
Explanation:
When a body is projected, the body experiences an acceleration in the vertical axis that is proportional to the acceleration due to gravity of the earth, which is equal to 9.81 m/s^2. In this case, the acceleration acts to stop the vertical motion of the paper plane, and hence is a deceleration, which explains the negative vertical acceleration.
Answer:
V = P = 0 m/s
Explanation:
When a pendulum bob is given an initial displacement or the initial velocity, it starts to execute periodic motion or simple harmonic motion. During this motion the kinetic and potential energy keeps interconverting. The kinetic energy becomes maximum at the lowest point, that is the mean point. Hence, the velocity is maximum at this point, as well. Similarly, at both extreme positions the potential energy becomes maximum due to maximum height, while the kinetic energy becomes zero at the highest point, that is extreme positions. At these, positions the velocity will be minimum and it will be zero due to zero kinetic energy. Hence, at both extreme positions the bob stops momentarily before, reversing the direction. Hence,
<u>V = P = 0 m/s</u>
Answer : The rocks and debris would never accrete into a planet.
Explanation : Gravity is an attraction force and dependents on the mass of the objects but in the absence of the force the rocks and debris would not come together to form a clump.
So, we can say that in the absence of gravity, the rock and debris would never accrete into a planet.
Answer:
(a) 
(b) 
(c) 
Solution:
As per the question:
Mass of Earth, 
Mass of Moon, 
Mass of Sun, 
Distance between the earth and the moon, 
Distance between the earth and the sun, 
Distance between the sun and the moon, 
Now,
We know that the gravitational force between two bodies of mass m and m' separated by a distance 'r' is given y:
(1)
Now,
(a) The force exerted by the Sun on the Moon is given by eqn (1):
(b) The force exerted by the Earth on the Moon is given by eqn (1):
(c) The force exerted by the Sun on the Earth is given by eqn (1):
