Answer:
33.33 %
Explanation:
given,
error last year = 63
error this year = 42
percent decrease in the error = ?
to find the percentage difference in the error formula used is
= 
= 
= 
= 33.33 %
Percentage decrease in the number of error is equal to 33.33%.
Answer:
Part(a): The angular acceleration is 
.
Part(b): The angular displacement is 
.
Explanation:
Part(a):
If 
be the initial angular speed, final angular speed and angular acceleration of the centrifuge respectively, then from rotational kinematic equation, we can write
where '
' is the time taken by the centrifuge to increase its angular speed.
Given, 
, 
and 
. From equation (
), the angular acceleration is given by
Part(b):
Also the angular displacement (
) can be written as
Answer:
B. τ = 16 Nm
Explanation:
In order to find the torque exerted by the weight attached to the heel of man's foot, when his leg is stretched out. We use following formula:
τ = Fd
here,
τ = Torque = ?
F = Force exerted by the weight = Weight = mg
F = mg = (4 kg)(10 m/s²) = 40 N
d = distance from knee to weight = 40 cm = 0.4 m
Therefore,
τ = (40 N)(0.4 m)
<u>B. τ = 16 Nm</u>
Answer:
Explanation:
Analysis of structure gives
a=gsinθ−μkgcosθ
Notice that all the expression are right but we want to know of we can simplify the expression further.
We want to analyse if we can still further simplify the expression,
Inspecting the Right hand side of the equation, we notice that the acceleration due to gravity is common to both side, so we can bring it out i.e.
So option a is wrong because the expression can be simplified further to
a=g(sinθ−μkcosθ)
Option b is right and the best option.
Since we are given that, g=9.8m/s²
We can as well substitute that to option a
So we will have
a=9.8metre/second²(sinθ−μkcosθ)
Also option C is correct but it is not best inserting the values of g directly without simplifying the expression first
So it will have been the best option if it was written as
a=9.8metre/second²(sinθ−μkcosθ)
So the best option is B.
Answer:
U for the reaction is 15,048.58 kJ/mol of pentane.
Explanation:
Quantity of heat required = heat capacity of bomb calorimeter × temperature rise = 5.23 kJ/C × (29.8 C - 23.7 C) = 5.23 kJ/C × 6.1 C = 31.903 kJ
Moles of pentane = mass/MW
Mass = 0.1523 g
MW of pentane (C5H12) = 72 g/mol
Moles of pentane = 0.1523/72 = 0.00212 mol
U for the reaction = quantity of heat required ÷ moles of pentane = 31.903 kJ ÷ 0.00212 mol = 15,048.58 kJ/mol
