1. C. Gravitational attraction exists between the two objects.
Explanation:
Gravitational attraction is always exerted between two objects which have mass, and its magnitude is given by:
where G is the gravitational constant, m1 and m2 the masses of the two objects, and r the separation between them. Since the two objects have for sure non-zero masses m1 and m2, even if they are 20 miles apart, the value of the gravitational attraction F is non-zero, so the correct answer is C.
2. D. Two atoms come together to form a molecule.
Explanation:
this outcome is actually caused by the electrostatic forces between the two atoms, not by gravitational force. In fact, gravitational force becomes relevant only when the masses of the two objects involved are large enough: this is the case for planets, stars, galaxies, and objects in the universe. However, two atoms have very small masses, so the gravitational force between them is really negligible. On this smaller scales, the electrostatic force is much stronger than the gravitational force, so the electrostatic force is the real responsible for the formation of bonds between atoms.
Answer:
D. Half as great
Explanation:
Since we know that the friction force between the surface of crate and ground is given as
so here we know that
= friction coefficient between two surfaces which depends on the effective contact area between two surfaces
= normal force due to the object
So when we turn the object on another side such that the surface area is half then the friction coefficient will become also half
So here the friction force will also reduce to half
so correct answer will be
D. Half as great
According to the statement we can deduce that the resulting amplitude of the wave pulse is zero when there is a destructive interference of two pulses and the chain is straight. At this point the potential energy will be zero, therefore when applying the energy conservation theorem, the potential energy must be equal to the kinetic energy and be conserved. The potential energy will be totally transferred as kinetic energy and therefore that will be the only energy present in the string.
Thus, the option C is correct.
Answer:
Explanation:
We shall apply length contraction einstein's relativistic formula to calculate the length observed by observer on the earth . For the observer , increased length will be observed for an observer on the earth
L= 2.05
The length will appear to be 2.05 m . and width will appear to be .5 m to the observer on the spaceship. . It is so because it is length which is moving parallel to the direction of travel. Width will remain unchanged.
