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2 years ago

A crane motor exerts 3,500.0 W to lift a load up 5 floors in 25.0 seconds. The crane did how much J of work.

Physics

1 answer:

sertanlavr [38]2 years ago

6 0

Answer:

87,500 J

Explanation:

Power = energy / time

3,500.0 W = E / 25.0 s

E = 87,500 J

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A cart of mass 6.0 kg moves with a speed of 3.0 m/s towards a second stationary cart with a mass of 3.0 kg. The carts move on a

katen-ka-za [31]

Answer:b

Explanation:

Given

mass of first cart $m_1=6 kg$

mass of second cart $m_2=3 kg$

velocity of first cart $v_1=3 m/s$

conserving momentum

$m_1v_1+m_2v_2=(m_1+m_2)v$

$6\times 3+3\times 0=(9)\cdot v$

$v=2 m/s$

Initial kinetic Energy $K.E._1=\frac{1}{2}m_1v_1^2+\frac{1}{2}m_2v_2^2$

$K.E._1=\frac{1}{2}\cdot 6\cdot 3^2+0$

$K.E._1=27 J$

Final Kinetic Energy

$K.E._2=\frac{1}{2}(m_1+m_2)v^2$

$K.E._2=\frac{1}{2}(6+3)\cdot 2^2=18 J$

Ratio of initial Kinetic Energy to the Final Kinetic Energy

$=\frac{27}{18}=1.5$

6 0

3 years ago

If two persons do the same amount of work , they may have different power ? why ?

iris [78.8K]

Hey there mate :)

Even if two persons are given the same work load, the speed of the work done gets different by the energy of those persons.

No one is sure that he/she can complete the work within the time. He may or may not.

Also, the physical characteristics makes the work different. If one person has so much power to work all day, the other person may not have.

Therefore, <em>even if two persons do the same amount of work , they may have different power</em><em>.</em>

4 0

2 years ago

A roundabout in a fairground requires an input power of 2.5 kW when operating at a constant angular velocity of 0.47 rad s–1 . (

natita [175]

Answer:

Explanation:

Since the roundabout is rotating with uniform velocity ,

input power = frictional power

frictional power = 2.5 kW

frictional torque x angular velocity = 2.5 kW

frictional torque x .47 = 2.5 kW

frictional torque = 2.5 / .47 kN .m

= 5.32 kN . m

= 5 kN.m

b )

When power is switched off , it will decelerate because of frictional torque .

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2 years ago

If the AMA of the inclined plane below is 2, calculate the IMA and efficiency. IMA = Efficiency =

wlad13 [49]

Answer:

IMA = 2.5 metres

EFFICIENCY = 80%

Explanation:

The AMA of a machine is referred to as the Actual Mechanical Advantage of a machine, calculated as the ratio of the output to the input force.

The Ideal Mechanical Advantage is the ratio of the input distance to the output distance.

From the diagram, the input distance which is also the distance moved by effort = 5metres

The load distance (output distance) = 2 metres

IMA = INPUT DISTANCE / OUTPUT DISTANCE

IMA = 5metres / 2 metres = 2.5 meters

Efficiency is the ratio of AMA TO IMA

AMA = 2, IMA = 2.5

EFFICIENCY = AMA / IMA

EFFICIENCY = (2 / 2.5) × 100%= 0.8 × 100%

EFFICIENCY = 80%

5 0

2 years ago

Hanna tosses a ball straight up with enough speed to remain in the air for several seconds?

olga_2 [115]

A) the velocity is 0 m/s

3 0

2 years ago

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