All categories

2 years ago

The kinetic energy of a body of mass 15 kg is 30 joule. What is its momentum?

Physics

1 answer:

lys-0071 [83]2 years ago

8 0

This problem is a piece o' cake, IF you know the formulas for both kinetic energy and momentum. So here they are:

Kinetic energy = (1/2) · (mass) · (speed²)

Momentum = (mass) · (speed)

So, now ... We know that

==> mass = 15 kg, and

==> kinetic energy = 30 Joules

Take those pieces of info and pluggum into the formula for kinetic energy:

Kinetic energy = (1/2) · (mass) · (speed²)

30 Joules = (1/2) · (15 kg) · (speed²)

60 Joules = (15 kg) · (speed²)

4 m²/s² = speed²

Speed = 2 m/s

THAT's all you need ! Now you can find momentum:

Momentum = (mass) · (speed)

Momentum = (15 kg) · (2 m/s)

Momentum = 30 kg·m/s

(Notice that in this problem, although their units are different, the magnitude of the KE is equal to the magnitude of the momentum. When I saw this, I wondered whether that's always true. So I did a little more work, and I found out that it isn't ... it's a coincidence that's true for this problem and some others, but it's usually not true.)

You might be interested in

20 points please answer

Anna [14]

Another way to test your question is to build your own miniature buildings. Depending on how in-depth you go, building could get a little pricey, but if you keep it basic there shouldn't be a problem. Decide on a certain number of foundations to test [maybe 3 or so] and try simulating an earthquake.
Hope this helps!

6 0

2 years ago

What do you know about potential energy? And how do we use it?

Liula [17]

Energy is the ability to do work or cause change. There are basically two main types of energy, kinetic and potential. Potential energy is energy that is stored. There are various types of stored, or potential energy. Chemical energy from a battery is a potential form of energy, elastic energy in a stretched rubber band is a form of potential energy, but the most commonly referred to form of potential energy in physics is that of gravitational potential energy. This is energy that is stored due to an object's position. It is dependent on the mass of the object, the height of the object above the ground or Earth, and the acceleration due to gravity.

7 0

3 years ago

What is the gravitational potential energy of a 3 kg ball that is 1 meter above the floor?

Sveta_85 [38]

Answer:

PE=mgh

M= Mass (kg)

G= Gravitational field strength (N/kg)

H= Hight (m)

PE= Gravitational Potential Energy (J)

Explanation:

Gravitational Potential Energy is the energy stored in a object due to its position above the Earth's surface.

7 0

3 years ago

A child on a skateboard experiences a 75 N force with an acceleration of 1.5 m/s2.

cupoosta [38]

Answer:

The mass of the child + skateboard is 50 kg

Explanation:

In this problem, we can apply Newton's second law:

F = ma

where

F is the net force on a system

m is the mass of the system

a is the acceleration of the system

In this problem, our system is the child + the skateboard. The net force on them is

F = 75 N

and their acceleration is

$a=1.5 m/s^2$

So we can re-arrange the equation above to find their combined mass:

$m=\frac{F}{a}=\frac{75}{1.5}=50 kg$

3 0

3 years ago

A uniform solid sphere has mass m= 7 kg and radius r= 0. 4 m. What is its moment of inertia about an axis tangent to its surface

lilavasa [31]

The moment of inertia of a uniform solid sphere is equal to 0.448 $kgm^2$ .

Given the following data:

Mass of sphere = 7 kg.

Radius of sphere = 0.4 meter.

<h3>How to calculate moment of inertia.</h3>

Mathematically, the moment of inertia of a solid sphere is given by this formula:

$I=\frac{2}{5} mr^2$

Where:

I is the moment of inertia.

m is the mass.

r is the radius.

Substituting the given parameters into the formula, we have;

$I=\frac{2}{5} \times 7 \times 0.4^2\\\\I=2.8 \times 0.16$

I = 0.448 $kgm^2$ .

Read more on inertia here: brainly.com/question/3406242

4 0

2 years ago