# 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

QUESTION POSTED 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.

Work done = Force * Distance

= 300 N * 1.5 m = 450 J

Power = 450 / 0.75 = 600 Watts.

B) Solar

Water cycle is driven primarily by the energy from the sun.

Water cycle is driven primarily by the energy from the sun.

ANSWERED AT 15/12/2019 - 11:04 PM

QUESTION POSTED AT 15/12/2019 - 11:04 PM

The **core **of the Sun has a temperature of about 15 million Celsius.

ANSWERED AT 15/12/2019 - 10:52 PM

QUESTION POSTED AT 15/12/2019 - 10:52 PM

A) The book has gravitational potential potential energy equal to m x g x h = 19,6 x m where m is the mass of the book. As the book is stationary, it has zero kinetic energy.

b) As the book falls, its potential energy decreases and is converted to its kinetic energy in the process, which increases. At a distance of about 1m from the ground, its potential energy is equal to its kinetic energy that is 9.8 x m where m is the mass of the book.

c) Just before the book hits the ground, it has maximum kinetic energy that is equal to its potential energy in part a). As its height from the ground is 0, its potential energy is zero is at this point.

b) As the book falls, its potential energy decreases and is converted to its kinetic energy in the process, which increases. At a distance of about 1m from the ground, its potential energy is equal to its kinetic energy that is 9.8 x m where m is the mass of the book.

c) Just before the book hits the ground, it has maximum kinetic energy that is equal to its potential energy in part a). As its height from the ground is 0, its potential energy is zero is at this point.

ANSWERED AT 15/12/2019 - 10:47 PM

QUESTION POSTED AT 15/12/2019 - 10:47 PM

The average dog lifespan is 12 years. The number of seconds is 12 x 60 x 60 = 43,200 s which is of the order 4 x s

ANSWERED AT 15/12/2019 - 10:47 PM

QUESTION POSTED AT 15/12/2019 - 10:47 PM

1) element

2) element

3) uppercase

4) lowercase

2) element

3) uppercase

4) lowercase

ANSWERED AT 15/12/2019 - 10:37 PM

QUESTION POSTED AT 15/12/2019 - 10:37 PM

A. they formed the tripartite pact

ANSWERED AT 15/12/2019 - 10:21 PM

QUESTION POSTED AT 15/12/2019 - 10:21 PM

A) the distance an object moves to the amount of time needed to travel the distance.

Speed is the rate of change of distance with time.

Speed is the rate of change of distance with time.

ANSWERED AT 15/12/2019 - 10:13 PM

QUESTION POSTED AT 15/12/2019 - 10:13 PM

If an automobile moving at high speed suddenly comes to a stop, you would have a large change in momentum. This relates to Newton's second law in the form F = delta p / delta t, where p is momentum (mv).

You could lessen the effect of the sudden stop on the passengers by changing the average force exerted on them. If you look at Newton's second law again, you can see that given some delta p, you can decrease F by increasing delta t. What this means is that if you increase the length of time over which the change in momentum occurs, you can decrease the average force exerted to obtain that change in momentum. This is the reason why landing on a soft cushion is preferable to landing on a concrete surface. The cushion gives way to any object falling on it while still providing some resistance (you don't stop as abruptly), so while your change in momentum is the same in both cases, you have a larger delta t in the case of the cushion.

You could lessen the effect of the sudden stop on the passengers by changing the average force exerted on them. If you look at Newton's second law again, you can see that given some delta p, you can decrease F by increasing delta t. What this means is that if you increase the length of time over which the change in momentum occurs, you can decrease the average force exerted to obtain that change in momentum. This is the reason why landing on a soft cushion is preferable to landing on a concrete surface. The cushion gives way to any object falling on it while still providing some resistance (you don't stop as abruptly), so while your change in momentum is the same in both cases, you have a larger delta t in the case of the cushion.

ANSWERED AT 15/12/2019 - 10:12 PM

QUESTION POSTED AT 15/12/2019 - 10:12 PM

**Answer:**

Saturn

**Explanation:**

There are 8 planets in the solar system. The smallest planet is mercury where as the largest planet is Jupiter. **The second largest planet is Saturn.** It is a Jovian planet **composed of gases mainly hydrogen and helium.** It is known for its **beautiful ring system **which are even visible when viewed from the earth. The rings are made of ice and rock. It is the **lightest planet**, its density being even lower than that of water.

ANSWERED AT 15/12/2019 - 09:46 PM

QUESTION POSTED AT 15/12/2019 - 09:46 PM

The distance is measured between the 'centers of mass',

or 'centers of gravity' of both objects. That's the point inside

the object where there's the same amount of mass in every

direction away from it.

If the object is something like a sphere, or a cube, or a uniform

wooden board, or anything "symmetrical", then the center of mass /

center of gravity is the actual center of the object. If the object has

some irregular shape, then it's harder to calculate or measure where

its center is.

ANSWERED AT 15/12/2019 - 09:39 PM

QUESTION POSTED AT 15/12/2019 - 09:39 PM

Since d= 163.2 and t = 2.4, we divide 163.2 by 2.4 to get **68 miles per hour.**

ANSWERED AT 15/12/2019 - 09:27 PM

QUESTION POSTED AT 15/12/2019 - 09:27 PM

The Axis forces in World War II were considered to be the bad guys from a historical perspective, the Axis forces composed of Hitler's Germany, Italy and Japan. These were the three major axis forces.

ANSWERED AT 15/12/2019 - 06:17 PM

QUESTION POSTED AT 15/12/2019 - 06:17 PM

Actually its 155, got this wrong on my test when I put 138 :)

ANSWERED AT 15/12/2019 - 06:10 PM

QUESTION POSTED AT 15/12/2019 - 06:10 PM

All we can say from the given information is that Matt's

average

(80 feet) / (40 seconds) = 2 feet per second .

We're not told whether his acceleration was constant

all the way down. IF it was, then we could use

Distance = (1/2 acceleration) x (time²).

80 ft = (1/2 acceleration) x (40 sec)²

Divide each side

by 1600 sec² : 80 ft / 1600 sec² = 1/2 acceleration

Multiply each side

by 2: 160 ft / 1600 sec² = acceleration

Acceleration =

ANSWERED AT 15/12/2019 - 06:10 PM

QUESTION POSTED AT 15/12/2019 - 06:10 PM

Potential energy = mass x g x height. So 600 J = mass x 9.81 m/s^2 x 4m, mass = 600 J/ (9.81 m/s^2 x 4m) = 600 J/39.24 m^2/s^2 = 15.3 kg

ANSWERED AT 15/12/2019 - 06:08 PM

QUESTION POSTED AT 15/12/2019 - 06:08 PM

Frequency = oscilations/vibrations per second

So the frequency is 30 000 Hz

So the frequency is 30 000 Hz

ANSWERED AT 15/12/2019 - 06:04 PM

QUESTION POSTED AT 15/12/2019 - 06:04 PM

**1. 5.5 m/s**

We can solve the problem by applying the law of conservation of momentum. The total momentum before the collision must be equal to the total momentum after the collision, so we have:

where

m1 = 0.4 kg is the mass of the ball

u1 = 18 m/s is the initial velocity of the ball

m2 = 0.2 kg is the mass of the bottle

u2 = 0 is the initial velocity of the bottle (which is initially at rest)

v1 = ? is the final velocity of the ball

v2 = 25 m/s is the final velocity of the bottle

Substituting and re-arranging the equation, we can find the final velocity of the ball:

**2. 22.2 m/s**

We can solve the problem again by using the law of conservation of momentum; the only difference in this case is that the bullet and the block, after the collision, travel together at the same speed v. So we can write:

where

m1 = 0.04 kg is the mass of the bullet

u1 = 300 m/s is the initial velocity of the bullet

m2 = 0.5 kg is the mass of the block

u2 = 0 is the initial velocity of the block (which is initially at rest)

v = ? is the final velocity of the bullet+block, which stick and travel together

Substituting and re-arranging the equation, we can find the final velocity of bullet+block:

**3. 6560 N**

The impulse exerted on the ball is equal to its change in momentum:

(1)

The impulse can be rewritten as product between force and time of collision:

while the change in momentum of the ball is equal to the product between its mass and the change in velocity:

So, eq.(1) becomes

where:

F = ? is the unknown force

is the duration of the impact

m = 0.16 kg is the mass of the ball

is the final velocity of the ball

is its initial velocity (we must add a negative sign, since it is in opposite direction to the final velocity)

So, by using the equation, we can find the force:

ANSWERED AT 15/12/2019 - 05:16 PM

QUESTION POSTED AT 15/12/2019 - 05:16 PM

C. the object's acceleration due to gravity is less on the moon

G = GM/r^2 where M is the mass of the body and r is the distance from the body to the point where g is being calculated. As the mass of the moon is much less than that of the earth, the acceleration due to gravity, g, is less on the moon.

G = GM/r^2 where M is the mass of the body and r is the distance from the body to the point where g is being calculated. As the mass of the moon is much less than that of the earth, the acceleration due to gravity, g, is less on the moon.

ANSWERED AT 15/12/2019 - 04:12 PM

QUESTION POSTED AT 15/12/2019 - 04:12 PM

Newtonian mechanics. IT is the system of mechanics which relies on Newton's laws of motion concerning the relations between forces acting and motions occurring.

ANSWERED AT 15/12/2019 - 04:01 PM

QUESTION POSTED AT 15/12/2019 - 04:01 PM

The answer is part **c that is What atoms make up water?**

This is because all of the option A, B and D require some sort of Physics to explain.

Such as how much energy is required, How fast or slow will something reach or how much force required on some object.

But option C, it just requires chemistry concepts as it is about the study of atoms and the usage of periodic table using covalent bonding.

ANSWERED AT 15/12/2019 - 04:01 PM

QUESTION POSTED AT 15/12/2019 - 04:01 PM

The image will be a virtual image. Using the lens equation: where o is the obejct distance, i the image distance and f the focal length, and rearranging the equation we have:

So if o is less than f, i is negative, that is the image displacement is negative, it is formed behind the lens and it is a virtual image.

So if o is less than f, i is negative, that is the image displacement is negative, it is formed behind the lens and it is a virtual image.

ANSWERED AT 15/12/2019 - 03:56 PM

QUESTION POSTED AT 15/12/2019 - 03:56 PM

For each revolution, the satellite covers the circumference

of its orbit.

The circumference of a circle is (pi) x (diameter).

Since the satellite is 22,500 miles from the center, that number

is the radius of the circle. The diameter is 45,000 miles.

The circumference is (pi) x (45,000 miles) = 141,372 miles

The satellite's average speed is 141,372 miles per day, or

(141,372 / 24) =

ANSWERED AT 15/12/2019 - 03:41 PM

QUESTION POSTED AT 15/12/2019 - 03:41 PM

**Answer: Option (B) is the correct answer.**

**Explanation:**

Given data is as follows.

Frequency = 0.0680 hertz = 0.0680 per second

Speed or velocity = 23.0 m/s

We can calculate the wavelength with the help of formula as follows.

=

= 338.23 meters

or, = 338 meters (approx)

Thus, we can conclude that **wavelength is 338 meters (approx).**

ANSWERED AT 15/12/2019 - 03:32 PM

QUESTION POSTED AT 15/12/2019 - 03:32 PM

This question could not come from any school source. If it did,

then you should always be suspicious of anything that comes

from that source. The question contains a fundamental mistake,

and misleads the student.

"Power", measured in "watts", is a rate, not a quantity. It tells

how fast you're using energy. You don't use some watts this

morning and some more watts this afternoon. That's like saying

that you'll drive some miles per hour today, and then you'll drive

some more miles per hour tomorrow. It doesn't work that way.

The heater doesn't use up some amount of watts. It uses up

some amount of energy. "Watts" is the measure of how fast

or slowly it uses up the energy.

This question makes sense if you get rid of the 'watts' and call it

'pints of milk' instead.

"My cats drink 3/5 pint of milk each hour.

How many pints of milk will they drink in 1/2 hour ?"

(1/2 hour) x (3/5 pint/hour)

= ( 1/2 x 3/5) (pint)

=

ANSWERED AT 15/12/2019 - 03:21 PM

QUESTION POSTED AT 15/12/2019 - 03:21 PM

Convert first the unit of their distances and their time.

Since 1 mile = 1.60934 km, then

300 miles * (1.60934 km / 1 mile) = 482.802 km

Since 1 hour = 60 minutes, then

5.5 hrs * (60 min / 1 hr) = 330 minutes

The speed is distance over time.

482.802 km / 330 minutes = 1.463 km/hr

Hope this helps ☺️ ✌️

Since 1 mile = 1.60934 km, then

300 miles * (1.60934 km / 1 mile) = 482.802 km

Since 1 hour = 60 minutes, then

5.5 hrs * (60 min / 1 hr) = 330 minutes

The speed is distance over time.

482.802 km / 330 minutes = 1.463 km/hr

Hope this helps ☺️ ✌️

ANSWERED AT 15/12/2019 - 03:13 PM

QUESTION POSTED AT 15/12/2019 - 03:13 PM

Sometimes if you have the word per, you need to multiply. In this problem, they are asking you to find the amount of meters a snail can travel per minute.They are giving you the amount of minutes, so in this case you multiply 15 times 0.30. The answer is 4.5 meters.

ANSWERED AT 15/12/2019 - 03:08 PM

QUESTION POSTED AT 15/12/2019 - 03:08 PM

I believe it would be distance

ANSWERED AT 15/12/2019 - 03:06 PM

QUESTION POSTED AT 15/12/2019 - 03:06 PM

Distance he covered = (7+5)km = 12 km

His displacement = = 8.6 km in the north-east direction.

His displacement = = 8.6 km in the north-east direction.

ANSWERED AT 15/12/2019 - 02:37 PM

QUESTION POSTED AT 15/12/2019 - 02:37 PM

D. direction

Velocity tells the speed of the object together with its direction whereas speed just tells how fast the object is travelling, it is the rate of change of distance per time, and does not give any information about the direction of travel.

Velocity tells the speed of the object together with its direction whereas speed just tells how fast the object is travelling, it is the rate of change of distance per time, and does not give any information about the direction of travel.

ANSWERED AT 15/12/2019 - 02:32 PM

QUESTION POSTED AT 15/12/2019 - 02:32 PM

B. erosion which cause people to move apart and loose touch.

ANSWERED AT 15/12/2019 - 02:31 PM

QUESTION POSTED AT 15/12/2019 - 02:31 PM