Any good and bad insulators of thermal energy, hot or cold, and why?
1 answer:
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Answer:
(a) The velocity (v) of the ball when reaches its maximum altitude is zero .
v= 0
(b) The acceleration of an object free fall motion is constant and is equal to the acceleration due to gravity,then, At maximum height the acceleration of ball is g =-9,8 m/s².
(c)velocity of the ball when it returns to the ground :
in direction -y
(d)a=g = -9,8 m/s² : acceleration of the ball when it returns to the ground
Explanation:
Ball Kinematics
We apply the free fall formula:
vf²=v₀²+2*a*y Formula (1)
y:displacement in meters (m)
v₀: initial speed in m/s
vf: final speed in m/s
a: acceleration
Data
v₀ = +5.00 m/s
Problem development
(a) What is its velocity when it reaches its maximum altitude?
in ymax, vf=0 , At maximum height the velocity is zero and the ball falls freely
(b) What is its acceleration at this point?
The acceleration of an object free fall motion is constant and is equal to the acceleration due to gravity,then, At maximum height the acceleration of ball is 9,8 m/s².
g= -9.8 m/s²
c) What is the velocity with which it returns to ground level?
We apply the Formula (1) to calculate the maximum height (h):
Ball movement up
vf²=v₀²+2*a*h
0 = (5)² +2*(-9.8)*h
19.6*h = 25
h= 25/19.6 = 1.275 m
Ball movement down
The distance the ball goes up is equal to the distance it goes down
h= 1.275 m , v₀=0
vf²=v₀²+2*a*h
vf²=0+2*(-9.8)*(-1.275)
in direction -y
(d) What is its acceleration at this point?
a is constant , a= g = -9.8 m/s²
Answer:
We can identify easily which block has more density, if we try to lift each one, and the heavier will be the one with more density. In this case the block of iron will be the one with more density.
Explanation:
To understand this we will give some numerical values to give the best explanation of this situation.
Let's say that we have the two blocks over one table, and over the table there is a special scale to measure the mass of an object.
Both block have the same dimensions, and seaching information of density by internet we find that the density for the iron is 7850 [kg/m^3], and the density for the aluminum is 2712 [kg/m^3]
Now the dimension of each bloack are 10*10*10 [cm] so, the volume will be 1000 [cm^3] = 0.001[m^3]
Now using the expression of density:
for the iron
for the aluminum
Therefore the weight of the iron will be always almost 3 times heavier than the weight of the aluminum.