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4 years ago

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A woman steps in front of a child to keep him from running off. which term best describes this example? negative work positive w

ork negative force positive force

2 answers:

vladimir1956 [14]4 years ago

5 0

Answer:

Negative force.

Explanation:

Here the woman is applying a force to stop the motion of the child so the nature of force is negative. after applying the force child stops without any displacement means displacement is zero.

Since we know that

WORK= FORCE * DISPLACEMENT

WORK= FORCE* 0 (ZERO)

WORK= ZERO.

means no work is done .only negative force would be the answer.

lana [24]4 years ago

4 0

Answer:

negative force

Explanation:

Here woman is applying the force to stop the child or to prevent him from running.

Here we know that the force applied by the woman is opposite to the motion of child but here the child is not displaced by this applied force but the child is only prevented his running.

So here the work done by the woman is zero as there is no displacement by this force.

But here we can say that the the force of woman is against the motion of child so here this force is opposite force and hence it is termed as negative force here.

so correct answer will be

negative force

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Answer:

a)1.13×10³

b)1.6×10³

Explanation:

Given:

Boltzmann's constant (K)=1.38×10^-23 J/K

atmoic mass of helium = 4 AMU or 4×1.66×10^-27kg

a)The formula for RMS speed (Vrms) is given as

$Vrms=\sqrt{\frac{3KT}{m} }$

where

K= Boltzmann's constant

T= temperature

m=mass of the gas

$Vrms=\sqrt{\frac{3\times 1.38\times 10^{-23}\times 206}{6.64\times 10^{-27}}}$

$Vrms=1.13\times 10^{3}m/s$

b) RMS speed of helium when the temperature is doubled

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$Vrms=1.598\times 10^{3}m/s$

4 0

4 years ago

Read 2 more answers

You get pulled over for running a red light. You explain to the police officer that the light appeared green to you due to the D

Ludmilka [50]

Answer:

$ 3085713685.71

Explanation:

$\lambda_0$ = Actual wavelength = 700 nm

$\lambda$ = Changed wavelength = 500 nm

Let the wavelength of red color be 700 nm and green be 500 nm

Change in wavelength is

$\Delta \lambda=700-500\\\Rightarrow \theta\lambda=200\ nm$

We have the relation

$\dfrac{\Delta\lambda}{\lambda_0}=\dfrac{v}{c}\\\Rightarrow v=\dfrac{\Delta\lambda}{\lambda_0}c\\\Rightarrow v=\dfrac{200}{700}\times 3\times 10^8\\\Rightarrow v=85714285.7143\ m/s$

The speed of the vehicle is 85714285.7143 m/s

$\dfrac{85714285.7143\times 3600}{1000}=308571428.571\ km/h$

By how much was the car speeding

$308571428.571-60=308571368.571\ km/h$

The number of 10 km/h in the above speed

$308571368.571\times\dfrac{1}{10}=30857136.8571$

Cost of the ticket

$30857136.8571\times 100=\$ 3085713685.71$

The cost of the ticket is $ 3085713685.71

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3 years ago

Read 2 more answers

A gas bottle contains 0.250 mol of gas at 730 mm hg pressure. if the final pressure is 1.15 atm, how many moles of gas were adde

Ludmilka [50]

Answer: 0.049 mol

Explanation:

1) Data:

n₁ = 0.250 mol

p₁ = 730 mmHg

p₂ = 1.15 atm

n₂ - n₁ = ?

2) Assumptions:

i) ideal gas equation: pV = nRT

ii) V and T constants.

3) Solution:

i) Since the temperature and the volume must be assumed constant, you can simplify the ideal gas equation into:

pV = nRT ⇒ p/n = RT/V ⇒ p/n = constant.

ii) Then p₁ / n₁ = p₂ / n₂

⇒ n₂ = p₂ n₁ / p₁

iii) n₂ = 1.15atm × 760 mmHg/atm × 0.250 mol / 730mmHg = 0.299 mol

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7 0

3 years ago

a load of 800 newton is lifted by an effort of 200 Newton. if the load is placed at a distance of 10 cm from the fulcrum. what w

nataly862011 [7]

Answer:

40 cm

Explanation:

We are given that

Load=800 N

Effort=200 N

Load distance=10 cm

We have to find the effort distance.

We know that

$load\times load\;distance=Effort\times effort\;distance$

Using the formula

$800\times 10=200\times effort\;distance$

Effort distance= $\frac{800\times 10}{200}$

Effort distance= $\frac{8000}{200}$

Effort distance=40 cm

Hence, the effort distance will be 40 cm.

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3 years ago

How long will it take a 2190 W motor to lift a 1.47 x 104 g box, 6.34 x 104 mm vertically.

-BARSIC- [3]

Answer:

4.2s

Explanation:

Given parameters:

Power = 2190W

Mass of box = 1.47 x 10⁴g

distance = 6.34 x 10⁴mm

Unknown:

Time = ?

Solution:

Power is the rate at which work is done;

Mathematically;

Power = $\frac{work done}{time}$

Time = $\frac{work done}{power}$

Work done = weight x height

convert mass to kg;

100g = 1kg;

1.47 x 10⁴g = 14.7kg

convert the height to m;

1000mm = 1m

6.34 x 10⁴mm gives 63.4m

Work done = 14.7 x 9.8 x 63.4 = 9133.4J

Time taken = $\frac{9133.4}{2190}$ = 4.2s

6 0

3 years ago