2km*1000=2000m
S=ut+1/2at^2
a=0,thus s=ut
2000=90t
t=2000/90
=22.22s(to 4 s.f)
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The ratio of the distance moved by the point at which the effort is applied in a simple machine to the distance moved by the point at which the load is applied, in the same time. In the case of an ideal (frictionless and weightless) machine, velocity ratio = mechanical advantage. Velocity ratio is sometimes called distance ratio.
Mass defect is the difference of the mass of the constituent particles (protons and neutrons) of the actual mass of the nucleus. The mass of a nucleus is actually less than the mass of the protons and neutrons.
This is how you calculate it for this problem.
lithium - 7 => 3 protons and 4 neutrons
mass of 3 protons = 3 * 1.007276 amu = 3.021828 amu
mass of 4 neutrons = 4 * 1.008665 amu = 4.03466
=> mass of 3 protons + 4 neutrons = 3.021828 amu + 4.03466 amu = 7.056488
Mass defect = mass of 3 protons and 4 neutrons - atomic mass of lithium =
Mass defect = 7.056488 amu - 7.016003 amu = 0.040485 amu
Answer:
Frictional force increases with the increase in the roughness of the surface.
Explanation:
You will see that the rougher the surface, the greater the wear and tear.
