Remember that the total velocity of the motion is the vector sum of the velocity you would have in still water and the stream. Always place the vectors carefully to be able to come up with an accurate sum vector.
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You must exert a force of 4.5 N on a book to slide it across a table. If you do 2.7J
1 answer:
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Answer:
3.15m³
Explanation:
To solve this problem, let us first find the mass of the petrol from the given dimension.
Mass = density x volume
Volume of petrol = 4.2m³
Density of petrol = 0.3kgm⁻³
Mass of petrol = 4.2 x 0.3 = 1.26kg
So;
We can now find the volume of the alcohol
Volume of alcohol =
Mass of alcohol = 1.26kg
Density of alcohol = 0.4kgm⁻³
Volume of alcohol = = 3.15m³
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
