In 1 hour, the hour hand sweeps across 1/12 of the clock's face. In 40 min, the hour hand travels (40 min)/(60 min) = 2/3 of the path it covers in an hour, so a total of 1/12 × 2/3 = 1/18 of the clock's face. This hand traces out a circle with radius 0.25 m, so in 40 min its tip traces out 1/18 of this circle's radius, or
1/18 × 2<em>π</em> (0.25 m) ≈ 0.087 m
The minute hand traverses (40 min)/(60 min) = 2/3 of the clock's face, so it traces out 2/3 of the circumference of a circle with radius 0.31 m:
2/3 × 2<em>π</em> (0.31 m) ≈ 1.3 m
The second hand completes 1 revolution each minute, so in 40 min it would fully trace the circumference of a circle with radius 0.34 m a total of 40 times, so it covers a distance of
40 × 2<em>π</em> (0.34 m) ≈ 85 m
Answer:
<span>5010J</span>
Explanation:
Work is force times distance, or
<span>W=F⋅d</span>.
Substitute in values from the question to get
<span>W=8.35⋅<span>102</span>N⋅6m=50.1⋅<span>102</span>Nm=5010<span>J</span></span>
<span>when it returns to its original level after encountering air resistance, its kinetic energy is
decreased.
In fact, part of the energy has been dissipated due to the air resistance.
The mechanical energy of the ball as it starts the motion is:
</span>

<span>where K is the kinetic energy, and where there is no potential energy since we use the initial height of the ball as reference level.
If there is no air resistance, this total energy is conserved, therefore when the ball returns to its original height, the kinetic energy will still be 100 J. However, because of the presence of the air resistance, the total mechanical energy is not conserved, and part of the total energy of the ball has been dissipated through the air. Therefore, when the ball returns to its original level, the kinetic energy will be less than 100 J.</span>
The "c) percent efficiency" could not be used to find the mechanical advantage of an inclined plane. There are two formulae that could be used to determine the mechanical advantage of an inclined plane which stated as MA = Length/rise and Wout=Win. MA is the mechanical advantage, Wout is the output force, Win is the input force, and "rise" is the height of the inclined plane<span>.</span>
Answer:
The acceleration is 1 cm/s^2.
Explanation:
The acceleration is defined as the rate of change of velocity.
Here, initial velocity, u = 3/1 = 3 cm/s
final velocity, v = 4/1 = 4 cm/s
time, t = 1 s
Let the acceleration is a.
Use first equation of motion
v = u + at
4 = 3 + 1 x a
a = 1 cm/s^2