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2 years ago

In which situation is no work considered to be done by a force?

1 answer:

8 0

If the angle is either 0 or 180, that means that there is either negative or positive work, so A and D are not correct.
If the angle is 45, then there is still some work involved.
The only option where there is no work done by a force is B. when the angle is between the force and displacement is 90.

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A student wants to use a ramp to move boxes into a truck bed that is 3 m high. He has a choice of 2 different ramps. The length

Morgarella [4.7K]

Answer:

The correct option is;

B. 8 m, because he has to apply less force over a greater distance

Explanation:

In the given question, in order for the student to lift the boxes onto the tuck with less amount of force, he applies the principle of Mechanical Advantage

The mechanical advantage is given by the measure by which a force is amplified through the use of a tool

Given that the work done = The force × The distance, we have

F₁ × d₁ = F₂ × d₂, which gives;

d₁/d₂ = F₂/F₁

Where;

F₁ = The input force

F₂ = The output force

d₁ = The input distance

d₂ = The output distance

The Mechanical advantage, MA = d₁/d₂ = F₂/F₁

Therefore, when the input distance is increased the input force will be reduced for a given output force

6 0

2 years ago

I have a voltage source of 12V but a light that only burns at 5V. The lamp works on 18 mA. Calculate the resistance that you EXT

Gala2k [10]

Answer:

The resistance that will provide this potential drop is 388.89 ohms.

Explanation:

Given;

Voltage source, E = 12 V

Voltage rating of the lamp, V = 5 V

Current through the lamp, I = 18 mA

Extra voltage or potential drop = 12 V - 5 V = 7 V

The resistance that will provide this potential drop (7 V) is calculated as follows:

$R = \frac{V}{I} = \frac{7 \ V}{18 \times 10^{-3} A} \ = 388.89 \ ohms$

Therefore, the resistance that will provide this potential drop is 388.89 ohms.

5 0

2 years ago

When it is at rotating at full speed, a disk drive in a certain old computer game system revolves once every 0.050 seconds. Star

Gemiola [76]

Answer:

α = 200*π rad/sec²

Explanation:

If the disk drive revolves once every 0.05 sec, this means that the angular velocity can be expressed as follows:

$\omega = \frac{2*\pi}{0.05s} = 40*\pi rad/sec$

(just applying the definition of angular velocity)
Now, it the disk started from rest, and took two revolutions to reach to full speed, assuming that the angular acceleration is constant, we can find the angular acceleration applying this kinematic equation:

$\omega_{f} ^{2} -\omega_{0} ^{2} = 2*\alpha * \Delta\theta$

where Δθ, is the angle rotated while it went from rest to full speed, i.e., 2 revolutions, or 2*π rads.
Replacing by the value that we found for ωf (as ω₀ = 0), we can solve for α :

$\alpha =\frac{\omega_{f}^{2} }{2*\Delta\theta} = \frac{(40*\pi)^{2} }{2*2*2*\pi } =\\ \\ \alpha = 200*\pi rad/sec2$

3 0

3 years ago

*NEED ANSWER QUICKLY!*

umka21 [38]

You would have to put the number together

8 0

2 years ago

Which option lists a form of kinetic energy followed by a form of potential

Artemon [7]

Answer:

D. Sound Energy, Magnetic energy

Explanation:

Sound energy is in motion, and Magnetic energy is about to be in motion.

6 0

2 years ago