Answer: The control group is the part where you see what happens when you change a variable you want to study/examine. Basically, you need the control group because you need something to see what happens when you change something.
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Answer:
a = 3.27 m/s²
F = 32.7 N
Explanation:
Draw a free body diagram. There are three forces:
Weight force mg pulling straight down.
Normal force N pushing perpendicular to the slope.
Friction force F pushing parallel up the slope.
Sum of forces in the parallel direction:
∑F = ma
mg sin θ − F = ma
Sum of torques about the cylinder's axis:
∑τ = Iα
Fr = ½ mr²α
F = ½ mrα
Since the cylinder rolls without slipping, a = αr. Substituting:
F = ½ ma
Two equations, two unknowns (a and F). Substituting the second equation into the first:
mg sin θ − ½ ma = ma
Multiply both sides by 2/m:
2g sin θ − a = 2a
Solve for a:
2g sin θ = 3a
a = ⅔ g sin θ
a = ⅔ (9.8 m/s²) (sin 30°)
a = 3.27 m/s²
Solving for F:
F = ½ ma
F = ½ (20 kg) (3.27 m/s²)
F = 32.7 N
according to the question are microwaves and X-rays
Volume=mass/density
volume=455.6/19.3
volume=23.6 mL
<span>120 revolutions per min is (20RPM)
120revolutions is 240 Pi radians (because 1 revolution is 2Pi rad)
angular velocity
w= 240Pixf, f is the frequency and f= 1/T, T =1mn=60s=period, so f=1/60=0.01Hz
so w = 240*Pi*0.01=12.56 rad /s
linear velocity can be found with
V =Rx w,
V=12.56 R the value depends on what value is the radius of both wheels
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