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Brut [27]
3 years ago
13

A student does 25 J of work on the handle of a pencil sharpener. If the pencil sharpener does 20 J of work on the pencil, what i

s the efficiency of the sharpener?
Physics
1 answer:
allsm [11]3 years ago
3 0

Answer:

80%

Explanation:

Efficiency of machine = work output/work input  ×100 %

From question, work output = 20J

Work input = 25J.

Therefore efficiency = 20/25 × 100 %

Efficiency = 20×4 %

Efficiency = 80%

I hope this was helpful, please mark as brainliest

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If the car traveled 754 meters in a straight line between 0 and 36 seconds, what was the
ArbitrLikvidat [17]

Answer:

20.94 m/s

Explanation:

Recall that average velocity is defined as:

V = distance / time

Then, for our case:

V = 754 m / 36 sec = 20.94 m/s

4 0
3 years ago
For a submarine, identify when it will have the GREATEST buoyant force acting on it. Assume that neither the volume of the subma
lidiya [134]

Answer: a, c, and g

Explanation:

Buoyant Force is an upward force acting on submerged object equal to weight of fluid displaced by the submerged object.

If no part is submerged (V = 0) that is volume. Therefore there is Zero Buoyant Force.

Fully submerged produces greatest buoyant force since greatest amount of fluid was displaced.

Whenever it is fully submerged it will have the greatest buoyant force.

Buoyant Force DOES NOT Depend on Depth

A fully submerged object displaces its volume in fluid

A floating object displaces its weight in fluid.

6 0
3 years ago
A woman lifts her 150 N child up one meter and carries her for a distance of 50 meters to the
Cloud [144]

7500J

Explanation:

Given parameters:

Weight of child = 150N

Height of lifting = 50m

Distance = 50m

Unknown:

Work done by the woman = ?

Solution:

Work done by a body is the force applied to move a body through a given distance.

  Work done = Force x distance

Weight is a force impacted by the mass of a body and the gravity on it.

 input the parameters:

   Work done = 150 x 50 = 7500J

learn more:

Work done brainly.com/question/9100769

#learnwithBrainly

3 0
3 years ago
A mass m = 3.9 kg hangs from a massless string wrapped around a uniform cylinder with mass Mp = 10.53 and radius R= 0.96 m. The
luda_lava [24]

Answer:

the rotational inertia of the cylinder = 4.85 kgm²

the mass moved 7.942 m/s

Explanation:

Formula for calculating Inertia can be expressed as:

I =\frac{1}{2}mR^2

For calculating the rotational inertia of the cylinder ; we have;

I = \frac{1}{2}m_pR^2

I = \frac{1}{2}*10.53*(0.96)^2

I=5.265*(0.96)^2

I=4.852224

I ≅ 4.85 kgm²

mg - T ma and RT = I ∝

T = \frac{Ia}{R^2}

a = \frac{g}{1+\frac{I}{mR^2}}

a = \frac{9.8}{1+\frac{4.85}{3.9*(0.96)^2}}

a = 4.1713 m/s²

Using the equation of motion

v^2 = u^2+2as \\ \\ v^2 = 2as \\ \\ v = \sqrt{2*a*s} \\ \\ v= \sqrt{2*4.1713*7.56} \\ \\ v = 7.942 \ m/s

3 0
3 years ago
Read 2 more answers
someone made a copy of an analog wave in a digital wave compare the copies with the original waves and explain which type of wav
lilavasa [31]

Answer: Analog transfer information quicker, example electromagnetic waves which are used in our modern day phones.

Explanation:  Digital signals are a more reliable form of transmitting information because an error in the amplitude or frequency value would have to be very large in order to cause a jump to a different value. Signals are composed of infinite possible values. Signals are composed of only two possible values: 0 or 1.

6 0
3 years ago
Read 2 more answers
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