Heather and Matt take 34 minutes to walk eastward along a straight road to a store 2.0km away. What is their average velocity in
1 answer:
Their average velocity is 0.98 m/s east.
Explanation:
The average velocity of an object is defined as the ratio between the displacement and the time taken:
The displacement is a vector connecting the initial point to the final point of motion: so, being displacement a vector, velocity is a vector as well, having the same direction of displacement.
Here, Heather and Matt walk 2.0 km eastward, so their displacement is
d = 2.0 km = 2000 m (east)
While the time they took is
Therefore, their average velocity is
And the direction is the same as the displacement (east).
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The angular speed of the merry-go-round reduced more as the sandbag is
placed further from the axis than increasing the mass of the sandbag.
The rank from largest to smallest angular speed is presented as follows;
[m = 10 kg, r = 0.25·R]
⇩
[m = 20 kg, r = 0.25·R]
⇩
[m = 10 kg, r = 0.5·R]
⇩
[m = 10 kg, r = 0.5·R] = [m = 40 kg, r = 0.25·R]
⇩
[m = 10 kg, r = 1.0·R]
Reasons:
The given combination in the question as obtained from a similar question online are;
<em>1: m = 20 kg, r = 0.25·R</em>
<em>2: m = 10 kg, r = 1.0·R</em>
<em>3: m = 10 kg, r = 0.25·R</em>
<em>4: m = 15 kg, r = 0.75·R</em>
<em>5: m = 10 kg, r = 0.5·R</em>
<em>6: m = 40 kg, r = 0.25·R</em>
According to the principle of conservation of angular momentum, we have;
The moment of inertia of the merry-go-round, = 0.5·M·R²
Moment of inertia of the sandbag = m·r²
Therefore;
0.5·M·R²· = (0.5·M·R² + m·r²)·
Given that 0.5·M·R²· is constant, as the value of m·r² increases, the value of
decreases.
The values of m·r² for each combination are;
Combination 1: m = 20 kg, r = 0.25·R; m·r² = 1.25·R²
Combination 2: m = 10 kg, r = 1.0·R; m·r² = 10·R²
Combination 3: m = 10 kg, r = 0.25·R; m·r² = 0.625·R²
Combination 4: m = 15 kg, r = 0.75·R; m·r² = 8.4375·R²
Combination 5: m = 10 kg, r = 0.5·R; m·r² = 2.5·R²
Combination 6: m = 40 kg, r = 0.25·R; m·r² = 2.5·R²
Therefore, the rank from largest to smallest angular speed is as follows;
Combination 3 > Combination 1 > Combination 5 = Combination 6 >
Combination 2
Which gives;
[<u>m = 10 kg, r = 0.25·R</u>] > [<u>m = 20 kg, r = 0.25·R</u>] > [<u>m = 10 kg, r = 0.5·R</u>] > [<u>m = </u>
<u>10 kg, r = 0.5·R</u>] = [<u>m = 40 kg, r = 0.25·R</u>] > [<u>m = 10 kg, r = 1.0·R</u>].
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