Answer:
0.71 m/s
Explanation:
We find the time it takes the stone to hit the water.
Using y = ut - 1/2gt² where y = height of bridge, u = initial speed of stone = 0 m/s, g = acceleration due to gravity = -9.8 m/s² (negative since it is directed downwards)and t = time it takes the stone to hit the water surface.
So, substituting the values of the variables into the equation, we have
y = ut - 1/2gt²
82.2 m = (0m/s)t - 1/2( -9.8 m/s²)t²
82.2 m = 0 + (4.9 m/s²)t²
82.2 m = (4.9 m/s²)t²
t² = 82.2 m/4.9 m/s²
t² = 16.78 s²
t = √16.78 s²
t = 4.1 s
This is also the time it takes the raft to move from 5.04 m before the bridge to 2.13 m before the bridge. So, the distance moved by the raft in time t = 4.1 s is 5.04 m - 2.13 m = 2.91 m.
Since speed = distance/time, the raft's speed v = 2.91 m/4.1 s = 0.71 m/s
Answer:
<h2>Your skull protects the most important part of all, the brain. You can feel your skull by pushing on your head, especially in the back a few inches above your neck.</h2>
Explanation:
Answer:
Since there is no external force, there is no change (movement) in the center of mass. Internally, the center of mass might change position, but the external result is still zero net velocity.
The net recoil velocity must be zero.
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.
Answer:
potential energy = mgh , where m is mass of body , g is acceleration due to gravity and h is given height
since both of the body are at same height above the ground , so the body having greater mass will have more potential energy
that is 20 kg body will have higher P.E
Explanation:
