<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.
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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>
The number of protons in an atom identifies the Atomic Number
Hope it helps!
Answer:
this is due to difference in speeds of sound and light
Explanation:
light has a speed of 3×10^8 m/s and it is seen at once because it takes negligible time due to very high speed and short distance that is why as soon as lightning occurs we can see it . since thundering sound travels with speed of sound which is about 330 to 340 m/s in air hence it takes some time as described in question as 6 seconds
Answer:
a,b,d and e are correct.
Explanation:
a) Change of temperature without change of velocity is a conclusive evidence of an interaction. As the temperature of a body will only change if heat energy is flows in or out of the body with surrounding. So, option a) is correct.
b) Change of the direction without change of speed is an evidence of an interaction. The direction changes when the object is under a perpendicular acceleration acceleration which clearly means the particle is interacting or external force applied. So, option b is correct.
d) Change of shape or configuration without change of velocity is conclusive evidence of an interaction. The shape can change only if external stress is applied on the particle. So, Option d is correct.
e) Change of identity without change of velocity is a conclusive evidence of an interaction. The identity of an object can only change if it interacts with surroundings. So, option e is correct
Therefore the only incorrect option is c .
Question: 18 kilogram Mass Block rest on level surface if the coefficient of static friction between the Block and the surface is 0.6 what horizontal force is required to just move the blcok ( take gravity as 10m/s2
)
Answer:
108 N
Explanation:
From the question,
Applying
F' = mgμ................ Equation 1
Where F' = Frictional force = horizontal force required to just move the block, m = mass of the block, g = acceleration due to gravity, μ = coefficient of static friction.
From the question,
Given: m = 18 kg, μ = 0.6, g = 10 m/s²
Substitute these values into equation 1
F' = 18×0.6×10
F' = 108 N
