Which statement about matter is correct? A) In matter, molecules never stop moving. B) In the solid state, molecules stop moving
2 answers:
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Answer:
v = 4.58 m/s
Explanation:
In order to calculate the speed of the skier when she gets the bottom of the hill, you have to calculate the speed of the skier when she crosses the rough patch.
To calculate the velocity at the final of the rough patch you take into account that the work done by the friction surface is equal to the change in the kinetic energy of the skier:
(1)
Where the minus sign means that the work is against the motion of the skier.
Wf: friction force
m: mass of the skier = 65.0kg
N: normal force = mg
g: gravitational acceleration = 9.8m/s^2
d: distance of the rough patch = 4.00m
v: speed at the end of the rough patch = ?
vo: initial speed of the skier = 6.85m/s
μk: coefficient of kinetic friction = 0.330
You replace the expression for the normal force in the equation (1), and solve for v:
Then, the speed fot he skier at the bottom of the hill is 4.58m/s
Answer:
Explanation:
Stiffness of spring k equal to 4 lb/ft.
Unstretched length of the spring L is equal to 0.5 feet.
Weight of the collar W is 15lb
Radius of curvature of curve guide is 1 feet
length of vertical rod is 1.5 feet
Initial speed of collar when released from rest at A is 0 feet per seconds
use the energy conservation equation
Estimate the potential energy , component as position B as below
Estimate the kinetic energy , component as position A as below
Estimate the kinetic energy , component as position B as below
Substitute 20.5lb- ft for
0.5lb-ft for
0lb -ft for
= 16.05ft/sec
Answer:
Explanation:
Given that:
A circuit with a lagging 0.7 pf delivers 1500 watts and 2100VA
Here:
the initial power factor i.e cos θ₁ = 0.7 lag
θ₁ = cos⁻¹ (0.7)
θ₁ = 45.573°
Active power P = 1500 watts
Apparent power S = 2100 VA
What amount of vars must be added to bring the pf to 0.85
i.e the required power factor here is cos θ₂ = 0.85 lag
θ₂ = cos⁻¹ (0.85)
θ₂ = 31.788°
However; the initial reactive power = P×tanθ₁
the initial reactive power = 1500 × tan(45.573)
the initial reactive power = 1500 × 1.0202
the initial reactive power = 1530.3 vars
The amount of vars that must therefore be added to bring the pf to 0.85
can be calculated as: