Answer:
a) v = 2,152 10⁸ m / s b) t = 2.71 10⁸ s or t = 85.93 year
Explanation:
a) In this special relativity exercise we have that time is measured in the same ship, so it is the proper time,
v = d / t
Let's reduce the distance to the SI system
d = 4.3 l and (9.46 1015 m / 1ly) = 40.678 10¹⁵ m
t = 5.0 y (365 day / 1 y) (24 h / 1 day) (3600s / 1h) = 1.89 10⁸ s
Let's calculate
v = 40.678 10¹⁵ / 1.89 10⁸
v = 2,152 10⁸ m / s
b) The time seen from the ground for which the ship moves is given by
t = t₀ / √ (1- (v/c)²)
Let's calculate
t = 1.89 10⁸ / √ (1 - (2.152 / 2.998)²)
t = 1.89 10⁸ / 0.6962
t = 2.71 10⁸ s
Let's reduce this time to years
t = 2.71 10⁸ s (1h / 3600s) (1day / 24h) (1 and / 365 d)
t = 85.93 year
<u>Answer:</u>
<em>A water strider can walk along the surface of earth due to the surface tension of water.
</em>
<u>Explanation:</u>
Fluids have a <em>tendency to shrink to minimum possible surface area</em> and this is called surface tension. It usually occurs due to the greater force of cohesion between molecules of same substance when compared to adhesive force between molecules of different substances. Objects with greater densities can float along water surface due to the <em>role played by surface tension.
</em>
When insects walk along the water surface they are pulled down due to gravity. But the force of attraction between the legs of the insect and water molecules is minimal. Thus the surface tension would always tend to maintain the <em>flatness of water overcoming</em> the push by the legs of the strider.
When the insect’s weight pulls it down , the surface tension pushes it upwards overcoming this force of gravity. This is how<em> water striders move along the surface of water. </em>
W=mg
W=75(1.6)
W=120N
a. 120N
Since the velocity of the real plane is 0, p=mv=0. So the paper airplane actually has more momentum since it's value is not 0.
Velocity ratio is also defined as the ratio of a distance through which any part of a machine moves, to that which the driving part moves during the same time. An object has a mechanical advantage if it exerts a force higher than the velocity ratio.
