Give reasons.
a. A stretched catapult has potential energy.
b A stone on ground has zero energy.
C. Rolling a drum is work against friction.
d. Lifting a stone is work against gravity.
e. Work and energy both have same unit.​

Answers

Answer 1
a. A stretched catapult can do work when released so it must have potential energy.

b. A stone on the ground will not move on its own ever again so it has zero energy.

c. In order to roll an object there must be a friction force between the object and the ground (otherwise it will slide)

d. To lift a stone you must overcome the weight which is the force due to gravity.

e. Work and energy are both measured in Joules.

Related Questions

4. Hijackers are taking over a plane, They tell the pilot to get to Spain as fast as possible. The plane goes from 900
km/hr (beginning speed) to 1140 km/hr (final speed) in just 6 seconds. What is the acceleration of the plane?

Answers

The acceleration is about 1457, because of the wind turbines and the way it’s going

Lucy and JoJo need to make 140 cupcakes for the school dance. Lucy made 35 of the cupcakes. JoJo made 42 cupcakes What fraction of the cupcakes do Lucy and JoJo still need to make?

Answers

Answer:

9/20

Explanation:

According to this question, Lucy and JoJo need to make 140 cupcakes for the school dance. Lucy made 35 of the cupcakes while JoJo made 42 cupcakes. This means that in total, (42 + 35) cupcakes has been made by both Lucy and JoJo

That is, 77 cupcakes out of 140 has been made. This is 77/140 i.e. 11/20

Since 77/140 cupcakes has been made, Lucy and JoJo still need to make;

140 - 77 = 63 cupcakes to meet up their target for the school dance.

This means that the fraction left is 63/140

63/140 in its lowest term is 9/20

Hence, 9/20 of the cupcakes still need to be made by Lucy and JoJo.

Explanation: 140 - 35 = 105 - 42 = 63

yare yare daze

I use tusk act 4 main

When performing a standard push-up, our hands should be placed on the ground... as close together as possible to make it the most challenging as close together as possible to make it the most challenging really wide to focus on chest development really wide to focus on chest development just outside our shoulders

Answers

Answer:

Kindly check the explanation section.

Explanation:

The statement given in the question or problem above is true or let's say it is correct. And the statement describes different kinds or types of push up.

Push up is a kind of excercise that is being done mainly to strengthen the arm and the cheat. The way one goes about it determines which part of the body one is strengthening.

The kind of push up in which one has to close up the gap between his or hands is known as the close push ups. This kind of push up strengthens the arm more than the other part of the body and the more one puts his or her hands closer the more problematic the push up excercise becomes.

Other types or kinds of push ups are the Slow Eccentric Push Ups, Wide Push Ups, Staggered Push Ups, T push ups, Fingertip Push Ups and many more.

Will was riding his bike when a dog ran out in front of him. He slammed on his brakes. During this quick stop, some of the mechanical energy (his motion) was changed into
A) heat energy.
B) light energy.
C) kinetic energy.
D) gravitational energy.

Answers

Answer:

A

Explanation:

big brain

During this quick stop, some of the mechanical energy (his motion) was changed into heat energy.

What is energy?

Energy is the ability to do work. There are different types of energy such as Heat energy, light energy, kinetic energy, and gravitational energy.

Heat is the energy that moves from one body to another when temperatures are different. Heat passes from the hotter to the colder body when two bodies with differing temperatures are brought together.

The joule is a unit of energy that serves as the SI unit for heat (J). The calorie (cal), which is defined as "the amount of heat necessary to raise the temperature of one gram of water from 14.5 degrees Celsius to 15.5 degrees Celsius," is another common unit of heat measurement.

Therefore, During this quick stop, some of the mechanical energy (his motion) was changed into heat energy.

To learn more about heat energy, refer to the link:

https://brainly.com/question/20038450

#SPJ6

Estimate the total mass of ocean on earth

Answers

1/4400 total mass on earth , weighting about 1,450,000,000,000,000,000 short tons of water

protons are present in sodium atom.
a 11
b 10
C 12
d 9

Answers

11

Explanation:

There are 11 protons in a sodium atom

An object with a charge of 1.2 C is located 4.5 m away from a second object that has a charge of 0.36 C. Find the electrical force that the objects exert on each other. Use 8.988×10 N⋅m2/C2 for the value of Coulomb's constant. Give your answer to two decimal places.

Answers

Answer:

[tex]1.917*10^8\ N[/tex]

Explanation:

Coulomb's law states that the electric force between two charges is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them. It is given by the formula:

[tex]F=k\frac{q_1q_2}{r^2}\\ \\q_1=first\ charge = 1.2C,q_2=second\ charge=0.36C,k=coulomb\ constant=8.988*10^9 N.m^2/C^2, r=distance=4.5m,F=force\\\\F=8.988*10^9*\frac{1.2*0.36}{4.5^2} =1.917*10^8\ N[/tex]

Yodelin has fifty quarters and dimes. Their total value is $9.80. Which of these systems of equations can be used to find the number of quarters (q) and
dimes (d) Yodelin has?

Answers

Answer:

q + d = 50

25q + 10d = 980

Explanation:

The equation that can be employed to determine the number of quarters(q), as well as, dimes(d) that Yodelin has would be:

q + d = 50...(1)

25q + 10d = 980...(2)

Multiplying (1) by 25

25q + 25d = 1250 ...(3)

25q + 10d = 980...(4)

subtracting (4) from (3)

15d = 270

d = 18

q = 50 - 18

    = 32

The system of the equations could be

q + d = 50

25q + 10d = 980

Calculation of the equation and the number of quarters and dimes:

Since Yodelin has fifty quarters and dimes. Their total value is $9.80.

So here the equations be

q + d = 50...(1)

25q + 10d = 980...(2)

Now we have to Multiplying (1) by 25

So,

25q + 25d = 1250 ...(3)

25q + 10d = 980...(4)

Now

subtracting (4) from (3)

15d = 270

d = 18

So,

q = 50 - 18

   = 32

Learn more about equation here; https://brainly.com/question/18648019

what is a unit of electrical flow called

Answers

Answer:

AMPERE - A unit of measure for the flow of current in a circuit. One ampere is the amount of current flow provided when one volt of electrical pressure is applied against one ohm of resistance. The ampere is used to measure electricity much as "gallons per minute" is used to measure water flow.

Explanation:

hope it helps

A unit of electrical flow is known as ampere

If an object is moving with constant acceleration, its velocity must

a
change by varying amounts depending on its speed.
b
always decrease.
c
be constant also.
d
change by the same amount each second.

Answers

change by the same amount each second. i think

what are two different examples of positive exeleration

Answers

Answer:Accelerating your car to get up to speed on a freeway

An airplane accelerating to take off

Accelerating out of the starting blocks at a track meet

Explanation:

#7 If the Moon’s mass was suddenly tripled, what would occur to the gravitational force between the Earth and the Moon?
(A) Gravitational force would increase by a factor of 3.
(B) Gravitational force would decrease by a factor of 3.
(C) Gravitational force would increase by a factor of 9.
(D) Gravitational force would decrease by a factor of 9.

Answers

Answer:

well it would be (A) Gravitational force would increase by a factor of 3.

Explanation:

because the moon is the only thing that gained mass not the Earth

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