Answer:
13.91 m/s
Explanation:
First we need to find the acceleration:
Acceleration = Force/mass
Acceleration = 36.7N/7.41 kg
Acceleration = 4.95 m/s² (rounded to two decimal places)
Then we find the velocity:
Velocity = Acceleration * Time
Velocity = 4.95 m/s² * 2.81 s
Velocity = 13.91 m/s (rounded to two decimal places)
Answer:
Mechanical advantage = 3
Explanation:
You exert a 100-N force on a pulley system to lift 300-N.
The mechanical advantage of the system is given by the ratio of output force to the input force.
Here, output force = 300 N and input force = 100 N
Mechanical advantage,
Mechanical advantage is 3 it means that there are 3 sections of rope support. Hence, this is the required solution.
Answer:
<h2>a) 50°</h2><h2>b) 40°</h2>
Explanation:
Check the complete diagram n the attachment below
a) The angle of incidence on a plane surface is the angle between the incidence ray and the normal ray acting on a plane surface. The normal ray is the ray perpendicular to the surface while the incidence ray is the ray striking a plane surface.
According to the diagram, the angle of reflection r₂ on M₂ is 90°-g where g is the angle of glance.
Given angle of glance on M₂ to be 40°, r₂ = 90-40 = 50°
According the second law of reflection, the angle of incidence = angle of reflection, therefore i₂ = r₂ = 50° (on M₂)
Also ∠OO₂O₁ = ∠OO₁O₂ = 40° (angle of glance on M₁){alternate angle}
The angle of incidence on M₁ = 90° - 40° = 50°
b) The angle of incidence to the surface of M₁(∠PO₁A)will be the angle of glance on M₁ which is equivalent to 40°
Answer:
C) steel turning to rust in salt air
Explanation:
The missing options are:
A) ice melting to form liquid water
B) water boiling to form steam
C) steel turning to rust in salt air
D) sugar dissolving into hot coffee
In a chemical change the atoms of the reacting compounds are reordered forming new compounds. In a chemical change, new compounds appear, but in a physical change not.
Then, change of states like ice melting and water boiling are not chemical changes.
During steel rust, components of steel, like iron, are oxidized, that is, reacts with oxygen forming oxides.
The dissolution of sugar into hot coffee is a physical change in which sugar molecules get further apart in the coffee, but they don't change.
Find how much work ∆<em>W</em> is done by the motor in lifting the elevator:
<em>P</em> = ∆<em>W</em> / ∆<em>t</em>
where
• <em>P</em> = 45.0 kW = power provided by the motor
• ∆<em>W</em> = work done
• ∆<em>t</em> = 20.0 s = duration of time
Solve for ∆<em>W</em> :
∆<em>W</em> = <em>P</em> ∆<em>t</em> = (45.0 kW) (20.0 s) = 900 kJ
In other words, it requires 900 kJ of energy to lift the elevator and its passengers. The combined mass of the system is <em>M</em> = (<em>m</em> + 490.0) kg, where <em>m</em> is the mass of the elevator alone. Then
∆<em>W</em> = <em>M</em> <em>g h</em>
where
• <em>g</em> = 9.80 m/s² = acceleration due to gravity
• <em>h</em> = 35.0 m = distance covered by the elevator
Solve for <em>M</em>, then for <em>m</em> :
<em>M</em> = ∆<em>W</em> / (<em>g h</em>) = (900 kJ) / ((9.80 m/s²) (35.0 m)) ≈ 2623.91 kg
<em>m</em> = <em>M</em> - 490.0 kg ≈ 2133.91 kg ≈ 2130 kg
