Answer:
When you are running the most important force that you should understand is friction. Friction is a force that opposes movement between two objects, but for runners friction makes you faster. Friction gives you a better and more efficient way to use your energy into speed.
Answer:
Option D
When the Moon is at right angles to the direction of the Sun.
Explanation:
The moon does not shine on its own, for example, like the sun that emits light as a consequence of its temperature. Instead, the moon is reflecting the sunlight (that is known as albedo).
The moon orbits the earth in a time 27.3 day, a sidereal period. According to that and the fact the Earth orbits the Sun, the moon will show different phases when is reflecting the sunlight along a month due to the configuration of those three celestial objects (Moon, Earth and the Sun).
When there is a Right angle between the Moon and to the direction of the Sun, half its face will appear to be illuminated in the night sky (that is called First Quarter).
Notice that when the Moon is between the Earth and the Sun it will be illuminated in its back, so it is not possible to see it from the Earth (that is called new moon).
However, a solar eclipse doesn't happens every month since the orbital plane of the moon is not in the same plane as the Earth's orbital plane with respect to the Sun.
As we know that time period of simple pendulum is given as
T = 2π √L/g
Answer:

Explanation:
When force applied to the end of the rod in perpendicular direction then net torque on the rod is given as


Now another force is applied at mid point of the rod at an angle of 30 degree with the rod
so new value of torque is given as



so we have

Cuz Of Newton’s third law, every actions there is an equal and opposite reaction.