A woman lifts a 300 newton child a distance of 1.5 meters in 0.75 seconds. What is her power output in lifting the child?

QUESTION POSTED AT 13/11/2019 - 05:21 PM

Answered by admin AT 13/11/2019 - 05:21 PM

Power = Work done / time

Work done = Force * Distance
                 =  300 N *  1.5 m =  450 J

Power =  450 / 0.75 = 600 Watts.
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Related questions

If a 2,300 kg car is accelerating at 16 m/s^2, what is the force it is producing?


Force = (mass) x (acceleration)

In order to accelerate the car at that rate, a force of

                  (2,300 kg) x (16 m/s²) = 36,800 newtons
                                               (about  8,270 pounds ... 4.14 tons !)

has to be coming from somewhere ... presumably from the straining,
screaming, smoking engine under the hood.

The force it might apply to an object it runs into will depend on the
shape and composition of that object.

ANSWERED AT 06/12/2019 - 03:37 PM


QUESTION POSTED AT 06/12/2019 - 03:37 PM

How much time would it take for an airplane to reach its destination. If it traveled at an average velocity of 790km/hr east for a distance of 4,700 kilometres

It would be 5.94 hours but you can round it to just 6 hours.

ANSWERED AT 06/12/2019 - 03:01 PM


QUESTION POSTED AT 06/12/2019 - 03:01 PM

A bus slams on its breaks and goes from 30 km/hr to 15km/hr in 4 seconds. What is its acceleration?


Acceleration = (change in speed) / (time for the change).

Change in speed = (15 - 30) = -15 km/hr
Time for the change = 4 sec

Acceleration = (-15 km/hr) / (4 sec) = -3.75 km/hr per second .

Is that a lot ?  Not much ?

Let's convert it to a unit that we can think about:

     (-15 km/hr) x (1,000 m/km) x (1 hr / 3,600 sec) =

           (-15 x 1,000) / (3,600)  =  -(4 and 1/6) m/sec .

So the acceleration of the bus is    -(4 and 1/6) m/sec² .

The negative sign means that it slowed down.

(4 and 1/6) m/sec²  is about  42%  of the acceleration of gravity ...
the acceleration the bus would have if it drove off of a cliff.

When the car or the bus you're riding in slows down at that rate,
you feel  42%  of your weight pulling you forward against your
seat belt.  That's quite a drastic acceleration !

ANSWERED AT 06/12/2019 - 02:36 PM


QUESTION POSTED AT 06/12/2019 - 02:36 PM

Compare the time taken by the RC car to cover the same distance. Do some go faster or slower?

There isn;t enough given values to define and determine what is asked. But since
distance = speed / time, time = distance / speed


Calculate the acceleration of a boat that has been cruising at 15 m/s but speeds up to 45 m/s in about 6 seconds. Don’t forget your units, m/s2. In order to calculate the acceleration of the boat we first have to identify the suited formula for acceleration in this scenario. 


Hence, a = vf – vi / t. Vi = 15 m/s Vf = 45 m/s T = 6 seconds   

Solution: 
A = 45 m/s – 15m/s / 6s 
A = 5m/s^2

ANSWERED AT 06/12/2019 - 12:11 PM


QUESTION POSTED AT 06/12/2019 - 12:11 PM

Anthony walks to the pizza place for lunch. he walk 1 km east, then 1 km south and then 1 km east again. what distance did he cover? what was his displacement?

He covered an amount of 2 km to east and one to south. the displacement, yeah i dont have that sorry :[

ANSWERED AT 06/12/2019 - 12:04 PM


QUESTION POSTED AT 06/12/2019 - 12:04 PM

A train is accelerating at a rate of 2 km/hr/s. If its initial velocity is 20 km/hr, what is its velocity after 30 seconds?

Here it is. *WARNING* VERY LONG ANSWER

________________________________________... 
11) If Galileo had dropped a 5.0 kg cannon ball to the ground from a height of 12 m, the change in PE of the cannon ball would have been product of mass(m),acceleration(g)and height(h) 

The change in PE =mgh=5*9.8*12=588 J 
______________________________________... 
12.) The 2000 Belmont Stakes winner, Commendable, ran the horse race at an average speed = v = 15.98 m/s. 

Commendable and jockey Pat Day had a combined mass =M= 550.0 kg, 

Their KE as they crossed the line=(1/2)Mv^2 

Their KE as they crossed the line=0.5*550*(15.98)^2 

Their KE as they crossed the line is 70224.11 J 

______________________________________... 
13)Brittany is changing the tire of her car on a steep hill of height =H= 20.0 m 

She trips and drops the spare tire of mass = m = 10.0 kg, 

The tire rolls down the hill with an intial speed = u = 2.00 m/s. 

The height of top of the next hill = h = 5.00 m 

Initial total mechanical energy =PE+KE=mgH+(1/2)mu^2 

Initial total mechanical energy =mgH+(1/2)mu^2 

Suppose the final speed at the top of second hill is v 

Final total mechanical energy =PE+KE=mgh+(1/2)mv^2 

As mechanical energy is conserved, 

Final total mechanical energy =Initial total mechanical energy 

mgh+(1/2)mv^2=mgH+(1/2)mu^2 

v = sq rt [u^2+2g(H-h)] 

v = sq rt [4+2*9.8(20-5)] 

v = sq rt 298 

v =17.2627 m/s 

The speed of the tire at the top of the next hill is 17.2627 m/s 
______________________________________... 
14.) A Mexican jumping bean jumps with the aid of a small worm that lives inside the bean. 

a.)The mass of bean = m = 2.0 g 

Height up to which the been jumps = h = 1.0 cm from hand 

Potential energy gained in reaching its highest point= mgh=1.96*10^-4 J or 1960 erg 

b.) The speed as the bean lands back in the palm of your hand =v=sq rt2gh =sqrt 0.196 =0.4427 m/s or 44.27 cm/s 
_____________________________ 
15.) A 500.-kg horse is standing at the top of a muddy hill on a rainy day. The hill is 100.0 m long with a vertical drop of 30.0 m. The pig slips and begins to slide down the hill. 

The pig's speed a the bottom of the hill = sq rt 2gh = sq rt 2*9.8*30 =sq rt 588 =24.249 m/s 
__________________________________ 
16.) While on the moon, the Apollo astronauts Neil Armstrong jumped up with an intitial speed 'u'of 1.51 m/s to a height 'h' of 0.700 m, 

The gravitational acceleration he experienced = u^2/2h = 2.2801 /(2*0.7) = 1.629 m/s^2 
______________________________________... 

EDIT 
1.) A train is accelerating at a rate = a = 2.0 km/hr/s. 

Acceleration 

Initial velocity = u = 20 km/hr, 

Velocity after 30 seconds = v = u + at 

Velocity after 30 seconds = v = 20 km/hr + 2 (km/hr/s)*30s = 

Velocity after 30 seconds = v = 20 km/hr + 60 km/hr = 80 km/ hr 

Velocity after 30 seconds = v = 80 km/hr=22.22 m/s 
_______________________________- 
2.) A runner achieves a velocity of 11.1 m/s 9 s after he begins. 

His acceleration = a =11.1/9=1.233 m/s^2 

Distance he covered = s = (1/2)at^2=49.95 m

ANSWERED AT 06/12/2019 - 11:27 AM


QUESTION POSTED AT 06/12/2019 - 11:27 AM

Your car is traveling at 70/mi/h (1000ft/s) your sneeze and your eyes close for 0.33 seconds how far did you travel during your sneeze?

If you're moving at 70 mi/hr, then you cover 33.88 feet in 0.33 sec. If you're moving at 1,000 ft/sec, then you cover 33 feet in 0.33 sec. 70 mph and 1,000 fps are not equivalent. 1,000 fps is about 682 mph, whereas 70 mph is about 103 fps.

ANSWERED AT 06/12/2019 - 10:54 AM


QUESTION POSTED AT 06/12/2019 - 10:54 AM

A small package is attached to a helium-filled balloon rising at 2 m/s. The package drops from the balloon when it is 14 meters above the ground. What is the velocity of the package just before it hits the ground?

I would assume air resistance is negligible and so the acceleration of the package would be approximately 9.81 m/s².

Taking downwards as positive, use v²=u²+2as.
v²=(-2)²+2(9.81)(14)
v=16.7 m/s

ANSWERED AT 06/12/2019 - 10:27 AM


QUESTION POSTED AT 06/12/2019 - 10:27 AM

Two stars in the night sky make an angle of 10^-3 radians at the eye of Matilda. If Arthur, who can just distinguish two spots, 0.5 cm apart, at a distance of 10 m views the stars, can he distinguish them as two distinct objects?


Let's calculate the angle between two spots, 0.5 cm apart,
that are 10m  away from you.

1 m  =  100 cm
10m  =  1,000 cm

The angle between the two spots is very very close to the angle
whose tangent is
                              0.5cm/1,000cm  =  0.0005 .

That angle is   tan⁻¹(0.0005) =  0.0005 radian  =  0.029 degree .

Matilda is looking at two stars that appear to be  0.001  radian apart.

That's (0.001 / 0.0005) = 2 = TWICE as far apart as Arthur can distinguish.

As long as Arthur and Matilda are on the same planet while looking at
these two stars ... or as long as they're even in the same solar system ...
Arthur will have no trouble separating them.

ANSWERED AT 06/12/2019 - 09:43 AM


QUESTION POSTED AT 06/12/2019 - 09:43 AM

Which of the following countries was NOT an Axis power? A. Japan B. Germany C. Portugal D. Italy

Portugal was not an axis power

ANSWERED AT 06/12/2019 - 09:34 AM


QUESTION POSTED AT 06/12/2019 - 09:34 AM

A tortoise is walking in the desert. It walks 6.4 meters in 4 minutes. What is its speed?

The speed of the tortoise can be calculate as follows:

 v=\frac{S}{t}

where

S is the distance travelled by the tortoise

t is the time taken


In this problem, S=6.4 m, while we should convert the time into seconds:

 t=4 min= 4\cdot 60 =240 s


Substituting the numbers into the equation, we find the speed:

 v=\frac{S}{t}=\frac{6.4 m}{240 s}=0.027 m/s

ANSWERED AT 06/12/2019 - 08:28 AM


QUESTION POSTED AT 06/12/2019 - 08:28 AM

An object moving in a circle at a constant speed is accelerating. Why? A. because it is going faster B. because it has constant velocity C. because its direction is changing D. because the distance it is traveling is changing


"Acceleration" does NOT mean 'speeding up'.  It means any change
in the speed or direction of motion ... speeding up, slowing down, or
moving in a curve.

An object moving in a circle at a constant speed is accelerating, because
when you're moving along a circle, your direction is constantly changing.

ANSWERED AT 06/12/2019 - 08:28 AM


QUESTION POSTED AT 06/12/2019 - 08:28 AM

What is Newtons second law of motion?

Hello there!

Explanation:

↓↓↓↓↓↓↓↓↓↓↓↓↓↓

Newton's second law of motion states that the total net force acting on an object is equal to mass times acceleration.

Newton's second law of motion formula:

↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

F=force=newtons=kg*\frac{m}{s^2}

M=mass (kg)

A-acceleration (\frac{m}{s^2})

F=ma

M=f/a

A=f/m

For example:

↓↓↓↓↓↓↓↓↓↓↓

Calculate the force needed to accelerate an object to 4.3 m/s². The object has a mass of 2.2 kg. Round the answer to the nearest tenth.

↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

A= 4.3 m/s²

M= 2.2 kg

F=??

F=ma

2.2 kg (4.3 m/s²)=9.46=9.5N

Answer⇒⇒⇒⇒⇒9.5N

Hope this helps!

Thank you for posting your question at here on Brainly.

Have a great day!

-Charlie

ANSWERED AT 06/12/2019 - 07:59 AM


QUESTION POSTED AT 06/12/2019 - 07:59 AM

Nearly all physics problems will use the unit m/s^2 for acceleration. Explain why the seconds are squared. Why isn't the unit given as m/s, as it is for speed


Because acceleration is not speed, and speed is not acceleration. 
I'm sure you would not ask "Why isn't temperature given in acres,
as it is for area ?"  Speed and acceleration are different things, so
it's only natural that they have different units.


The magnitude (size) part of acceleration is:

         (how much speed changes) per second.

Are you speeding up ?
Are you traveling (2 meters per second) faster every second ?
Then your acceleration is

           (2 meters per second) per second .

When you write that phrase as an algebraic expression, it's

           (2 m/sec) / sec

and when you simplify that fraction, you get        2 m/sec² .


ANSWERED AT 06/12/2019 - 07:40 AM


QUESTION POSTED AT 06/12/2019 - 07:40 AM

The average distance from the sun to Pluto is approximately 6.10 time 10^9 km. How long does it take light from the sun (384,000 km/s) to reach Pluto?


From the information as given in the question, the transit time
for light from the sun would be

       (6.1 x 10⁹ km) / (3.84 x 10³ km/sec) = 15,885 seconds (rounded).
                                                                       (4.4 hours) .
==============================

-- A better figure for Pluto's average distance from the sun is  5.874 x 10⁹ km.

-- " 384,000 km/sec " is about 28% too high for the speed of light.
    A much better figure is  300,000 km/sec.

Using these numbers, the transit time is

           (5.874 x 10⁹ km) / (3 x 10⁵ km/sec)  =  19,580 seconds
                                                                             (5.4 hours)

ANSWERED AT 06/12/2019 - 07:12 AM


QUESTION POSTED AT 06/12/2019 - 07:12 AM

Britain and France signed an entente and became the a. Central Forces. c. Central Powers. b. Allied Forces. d. Axis Powers.

Im pretty sure that it is allied forces

ANSWERED AT 06/12/2019 - 07:11 AM


QUESTION POSTED AT 06/12/2019 - 07:11 AM

A sample has a mass of 15 g and a volume of 3mL


Thanks for sharing.   The density of the sample
is 5 g/cm³. Do you have a question to ask ?

ANSWERED AT 06/12/2019 - 07:03 AM


QUESTION POSTED AT 06/12/2019 - 07:03 AM

A penny dropped into a wishing well reaches the bottom in 1.50 seconds. what was the velocity at impact


On Earth, the acceleration of gravity is 9.8 m/s² downward. 
This means that any falling object gains 9.8 m/s of speed downward
for every second it falls. 

Since the penny fell for 1.5 seconds, its downward speed at the
end of that time is (1.5 x 9.8) = 14.7 m/s faster than at the beginning
of that time. 

Since it was dropped gently from somebody's hand ... and not THROWN
down ... its speed at the beginning is zero.  So its speed after 1.5 seconds
is 14.7 m/s, and its velocity after 1.5 seconds is 14.7 m/s downward.

ANSWERED AT 06/12/2019 - 07:03 AM


QUESTION POSTED AT 06/12/2019 - 07:03 AM

What would be the resistivity of a perfect conductor in ohm-meters? infinity zero 100 1

The answer would be B. Zero

ANSWERED AT 06/12/2019 - 05:42 AM


QUESTION POSTED AT 06/12/2019 - 05:42 AM

Two people pull upwards to the left and upwards to the right with two large forces in order to lift a 1kg book by two cables. If each cable make 1- degree angle with the horizontal, then what is the tension in the cables?


The weight of the book is (mass) x (gravity) = (1kg) x (9.8m/s²) = 9.8 newtons
                                                                                            (about 2.2 pounds)
The upward force on the book is the sum of the
upward force from each cable (each person).

The forces from the two people must be equal, otherwise the book
would move sideways one way or the other.

Now for the big cookie:  If the cables are within 1 degree of
being horizontal, then how much of each person's force winds
up being vertical to lift the book ?

If a force 'F' is directed 1 degree above horizontal, then
its strength in the horizontal direction is   F x cos(1), and
its strength in the vertical direction is   F x sin(1).

Each person is pulling with a force  F.
His vertical component is  F x sin(1).
Two of these hold the 1-kg book up.

                             2F sin(1) = 9.8 newtons

Divide each side by 2 :      F sin(1) = 4.9 newtons

Divide each side by  sin(1)    F = 4.9 / sin(1) = 280.7 newtons (rounded)
                                                                    (about 63 pounds)

This is the tension in each cable.               
____________________________________________

That's why, technically, it's impossible to make the cable or string
perfectly horizontal, even when there's nothing hanging from it. 
When the force is perfectly horizontal, its vertical component is
zero, so it would take an infinite force to hold anything horizontal,
even the weight of the string itself. 
From another viewpoint ... If the string or cable is almost horizontal,
then the tension in it is already so great that you can break it with
just a light push in the center with your finger.

ANSWERED AT 06/12/2019 - 05:31 AM


QUESTION POSTED AT 06/12/2019 - 05:31 AM

How much time would it take for the sound of thunder to travel 1,500 meters if sound travels at a speed of 330 m/sec?


(1,500 meters) x (1 sec / 330 meters) = (4 and 18/33) seconds

                                                                 (4.55 sec, rounded)

ANSWERED AT 06/12/2019 - 05:27 AM


QUESTION POSTED AT 06/12/2019 - 05:27 AM

A force vector F1 points due east and has a magnitude of 200 Newtons, A second force F2 is added to F1. The resultant of the two vectors has a magnitude of 400 newtons and points along the due east/west line. Find the magnitude and direction of F2. Note that there are two answers.

A force vector F1 points due east and has a magnitude of 200 Newtons, A second force F2 is added to F1. The resultant of the two vectors has a magnitude of 400 newtons and points along the due east/west line. Find the magnitude and direction of F2. Note that there are two answers. The given values are
F1 = 200 N
F2 =? Total = 400 N

Solution: F1 + F2 = T 200 N + F2 = 400N
F2 = 400 - 200
F2 = 200 N



ANSWERED AT 06/12/2019 - 04:07 AM


QUESTION POSTED AT 06/12/2019 - 04:07 AM

If a bird flies from its nest to the ground and back are the distance and displacment the sam

No. They are different. The bird's distance for that period of time is double the height of the nest above the ground. His displacement for the same time is zero ... the length between the start point and end point.

ANSWERED AT 06/12/2019 - 03:59 AM


QUESTION POSTED AT 06/12/2019 - 03:59 AM

How much time would it take for the sound of thunder to travel 1500 meters of sound travels at a speed of 330 m/sec?

1500m
-----------
330ms-1
= 4.5455 s

ANSWERED AT 06/12/2019 - 03:55 AM


QUESTION POSTED AT 06/12/2019 - 03:55 AM

How far can a person run in 15 minutes if he or she runs at an average speed of 16 km/hr

4 km/hr. There are four quarters in an hour, so just divide 16 by 4 and you get 4. It is directly proportional.

ANSWERED AT 06/12/2019 - 03:38 AM


QUESTION POSTED AT 06/12/2019 - 03:38 AM

Otto emissions is driving his car at 25.0m/s. Otto accelerates at 2.0 meters per seconds squared for 5 seconds. Otto then maintains a constant velocity for 10 more seconds. Determine the distance Otto traveled during the entire 15 seconds

Given:
25.0 m/s -speed of his car
2.0 m/s^2 for 5s - acceleration
10s- constant velocity

Asked: total distance traveled during the entire 15 seconds.
( see attached file for the solution)

ANSWERED AT 06/12/2019 - 03:11 AM


QUESTION POSTED AT 06/12/2019 - 03:11 AM

How many years older will you be 1.20 billion seconds from now? (Assume a 365-day year.)

38 years older miss =) im possitive

ANSWERED AT 06/12/2019 - 02:55 AM


QUESTION POSTED AT 06/12/2019 - 02:55 AM