The wall will push back, in exactly the opposite direction, and with
exactly the same size force.
That's why the net force on the palm of your hand is zero, and that
in turn is the reason that your hand doesn't accelerate.
If you keep increasing the strength of your push, then eventually you
exceed the force that the wall is capable of delivering. Then the wall
crumbles and falls, your hand accelerates in the direction you're pushing,
and the crowd goes wild !
A) change in ht after 180m = 180 * sin(4-deg.) = 12.56m
net work done by gravity on the cyclist = mass * gravity * height diff.
= 85 * 9.8 * 12.56
= 10470J
= 10.5kJ
B) Kinetic energy = 1/2 * mass * vel.^2 = work done by gravity = 10470J
vel.^2 = 10470 * 2 / 85 = 246.4
vel. = 15.7m/s
Answer:
use the formula negative -eE/A×t
Given:
ρ = 13.6 x 10³ kg/m³, density of mercury
W = 6.0 N, weight of the mercury sample
g = 9.81 m/s², acceleration due to gravity.
Let V = the volume of the sample.
Then
W = ρVg
or
V = W/(ρg)
= (6.0 N)/[(13.6 x 10³ kg/m³)*(9.81 m/s²)]
= 4.4972 x 10⁻⁵ m³
Answer: The volume is 44.972 x 10⁻⁶ m³
