Answer:
x ≈ 56 m
Explanation:
vertical initial velocity = = 25 m/s* sin(30°)= 12.5 m/s
height = h
t- time is found solving quadratic equation.
horizontal velocity =
Horizontal velocity is constant, so distance
How are forest fires beneficial to conifers like Jack Pines? a. Jack pine seeds are protected by forest fires. b. Pine cones are
2 answers:
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A) initial volume
We can calculate the initial volume of the gas by using the ideal gas law:
where
is the initial pressure of the gas
is the initial volume of the gas
is the number of moles
is the gas constant
is the initial temperature of the gas
By re-arranging this equation, we can find:
2) Now the gas cools down to a temperature of
while the pressure is kept constant:
, so we can use again the ideal gas law to find the new volume of the gas
3) In a process at constant pressure, the work done by the gas is equal to the product between the pressure and the difference of volume:
by using the data we found at point 1) and 2), we find
where the negative sign means the work is done by the surrounding on the gas.
We can calculate the initial volume of the gas by using the ideal gas law:
where
By re-arranging this equation, we can find
2) Now the gas cools down to a temperature of
while the pressure is kept constant:
3) In a process at constant pressure, the work done by the gas is equal to the product between the pressure and the difference of volume:
by using the data we found at point 1) and 2), we find
where the negative sign means the work is done by the surrounding on the gas.
Answer:
(a) Ff = 0.128 N
(b μk = 0.1135
Explanation:
kinematic analysis
Because the hockey puck moves with uniformly accelerated movement we apply the following formulas:
vf=v₀+a*t Formula (1)
d= v₀t+ (1/2)*a*t² Formula (2)
Where:
d:displacement in meters (m)
t : time in seconds (s)
v₀: initial speed in m/s
vf: final speed in m/s
a: acceleration in m/s
Calculation of the acceleration of the hockey puck
We apply the Formula (1)
vf=v₀+a*t v₀=5.8 m/s , vf=0
0=5.8+a*t
-5.8 = a*t
a= -5.8/t Equation (1)
We replace a= -5.8/t in the Formula (2)
d= v₀*t+ (1/2)*a*t² , d=15.1 m , v₀=5.8 m/s
15.1 = 5.8*t+ (1/2)*(-5.8/t)*t²
15.1= 5.8*t-2.9*t
15.1= 2.9*t
t = 15.1 / 2.9
t= 5.2 s
We replace t= 5.2 s in the equation (1)
a= -5.8/5.2
a= -1.115 m/s²
(a) Calculation of the frictional force (Ff)
We apply Newton's second law
∑F = m*a Formula (3)
∑F : algebraic sum of the forces in Newton (N)
m : mass in kilograms (kg)
a : acceleration in meters over second square (m/s²)
Look at the free body diagram of the hockey puck in the attached graphic
∑Fx = m*a m= 115g * 10⁻³ Kg/g = 0.115g , a= -1.12 m/s²
-Ff = 0.115*(-1.115) We multiply by (-1 ) on both sides of the equation
Ff = 0.128 N
(b) Calculation of the coefficient of friction (μk)
N: Normal Force (N)
W=m*g= 0.115*9.8= 1.127 N : hockey puck Weight
g: acceleration due to gravity =9.8 m/s²
∑Fy = 0
N-W=0
N = W
N = 1.127 N
μk = Ff/N
μk = 0.128/1.127
μk = 0.1135
