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3 years ago

13

How much work is done by a babysitter who uses 8000 W of power to lift a baby in 2s?

1 answer:

Solnce55 [7]3 years ago

5 0

Answer:

16000 Joules

Explanation:

8000W x 2

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Calculate the amount of heat (in kj) required to convert 74.6 g of water to steam at 100°c

Kryger [21]

You just need the energy of turning of water in to steam. Water is a little funny because once water gets to 100 degrees C, it stops changing in temperature whilst it all turns to steam. The amount of energy required to turn 1 gram of water into steam is 2257 Joules. We call this the latent heat of vaporisation. So to turn 74.6 grams of water to steam, you would need:

2257J/gram x 74.6g = 168,372.2 J = 168.4 kJ

(<span></span><em>latent heat of vaporisation: 2257 J/gram</em>)

7 0

3 years ago

An object of mass m is placed on Spring A, which is compressed by distance x. The spring is released and the velocity of the pus

ss7ja [257]

Answer:

C

Explanation:

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3 years ago

A three-wheeled car moving along a straight section of road starts from rest, accelerating at 2.00 m/s2 until it reaches a speed

DiKsa [7]

Answer:

(a) Total time = 105.5 sec

(b)average speed = 31.26 m/sec

Explanation:

We have given that three-wheeled car starts from rest that initial velocity u = 0 m/sec

Final velocity = 35 m/sec

Acceleration $a=2m/sec^2$

According to first law of motion we know that v = u+at

So $35=0+2\times t$

t = 17.5 sec

After this car travels 83 sec at a constant speed and after that it takes 5 sec additional time to stop

(a) So total time in which car is in motion = 17.5+83+5 = 105.5 sec

(b) Total distance traveled during first 17.5 sec

$s=ut+\frac{1}{2}at^2=0\times 17.5+\frac{1}{2}\times 2\times 17.5^2=306.25m$

Distance traveled in 83 sec with with velocity of 35 m/sec = $35\times 83=2905m$

For next 5 second

Initial velocity u = 35 m/sec

Final velocity = 0 as finally car stops

So $a=\frac{v-u}{t}=\frac{0-35}{5}=-7m/sec^2$

Distance traveled $s=ut+\frac{1}{2}at^2=35\times 5+\frac{1}{2}\times -7\times 5^2=87.5m$

So total distance traveled = 306.25+2905+87.5 = 3298.75 m

Total time = 105.5 sec

So average speed $=\frac{total\ distance}{total\ time }=\frac{3298.75}{105.5}=31.26m/sec$

5 0

3 years ago

An object with a kinetic energy of 2160 J has a new mass of 120kg. What is it's velocity?

nadya68 [22]

Answer:

The velocity is 6 m/s

Explanation:

We use the formula of kinetic energy=

Ec= 1/2 x m x v2

2160 J = 1/2 x 120 kg x v2

v = $\sqrt[n]{x} 2160Joulex2/120kg\\$

v= 6m/s

1Joule= 1 kgm2/s2

4 0

3 years ago

In an experiment similar to the one you performed in Week 3, an experimenter measures the count rate of a radioactive element 10

suter [353]

Answer:

The answer is "1.5625".

Explanation:

Please find the complete question with its solution file in the attachment.

3 0

3 years ago