An apple in a tree has a mass of 0.21 kg. If it is 7.2 meters above the ground, how much potential energy does it have?

1. A man throws a ball up with a velocity of 30 m/s. How high does it get?

ElenaW [278]

Yes the answer is g=5

8 0

2 years ago

All of the following involve waves of electromagnetic energy except _______.

r-ruslan [8.4K]

All of the following involve waves of electromagnetic energy except the rumble of thunder during a storm.

Electromagnetic waves are used to transmit long/short/FM wavelength radio waves, and TV/telephone/wireless signals or energies. They are also responsible for transmiting energy in the form of microwaves, infrared radiation (IR), visible light (VIS), ultraviolet light (UV), X-rays, and gamma rays.

The correct answer between all the choices given is the second choice or letter B. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.

6 0

3 years ago

Read 2 more answers

Here's a basketball problem: A 87.2 kg basketball player is running in the positive direction at 7.0 m/s. She is met head-on by

Ray Of Light [21]

Answer:

2.47 m/s backwards

Explanation:

From the law of conservation of momentum,

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂...................... Equation 1

Where m₁ and m₂ = mass of the first basketball player and second basket ball player respectively, u₁ and u₂ = initial velocity of the first basket player and the second basketball player respectively, v₁ and v₂ = The final velocity of the first basket ball player and second basket ball player respectively.

Making v₁ the subject of the equation,

v₁ = (m₁u₁ + m₂u₂ - m₂v₂)/m₁.......................... Equation 2.

Given: m₁ = 87.2 kg, m₂ = 102.0 kg, u₁ = 7.0 m/s, u₂ = -5.2 m/s, v₂ = 2.9 m/s

Note: u₂ is negative because it moves towards the first basket ball player.

Substitute into equation 2

v₁ = [87.2(7.0)+102(-5.2) - (102×2.9)]/87.2

v₁ = (610.4-530-295.8)/87.2

v₁ = -215.4/87.2

v₁ = -2.47 m/s.

Thus the velocity of the 87.2 kg player = 2.47 m/s backwards.

7 0

3 years ago

Two objects are raised off the ground and one of them is three times as high as the other one. How do their potential energy com

DochEvi [55]

The potential energy of any object depends on its mass as well as its height off the ground.

Potential energy = mass x gravity x height.

We don't have enough information to compare the potential energies of these two objects because we don't know their masses.

3 0

3 years ago

(A) how much work is done when you push a crate horizontally with 100 N across a 10-m factory floor?

Mila [183]

Answer:

A) 1000 joules

Explanation:

In general work is given by the equation:

$W=\intop_{a}^{b}\overrightarrow{F}\cdot d\overrightarrow{s}$ (1)

A) With $\overrightarrow{s}$ the displacement and $\overrightarrow{F}$ the force applied, because the force and the displacement are parallel (the crate is pushed horizontally) $\overrightarrow{F}\cdot d\overrightarrow{s}$ is simply $F\,ds$ , and because the path is a straight line and the force is constant work is:

$W=FS$ (2),

$W=(100)(10)=1000\,J$

B) The work-energy theorem says that the total work on a body is equal to the change on kinetic energy:

$W_{tot}=\varDelta K$ (3)

The total work on the crate is the work done by the push and plus the work of the friction $W_{tot}=W + W_{f}$ (4) , as (A) because forces are parallel to the displacement $W= FS$ (5) and $W_{f}=-fS$ (6), the due friction always has negative sign because is opposite to the displacement, using (6), (5) and (4) on (3):

$FS-fS=\varDelta K$ (3)

$1000-(70)(10)=300\,J$

C) The energy is lost by friction, so the amount of energy turned into heat is the work the friction does:

$Q=fS=(70)(100)=700\,J$ (3)

6 0

3 years ago