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3 years ago

7.

Physics

2 answers:

SSSSS [86.1K]3 years ago

7 0

Free fall is a special type of motion in which the gravity is the only force that acting upon an object.

Explanation:

In the free fall the object have gravity force only. when you dropped the ball from top of the building, and it will start falling. The balls falls due to gravity. Imagine when you have held the ball in your hand, gravity is acting, but the frictional force between your fingers and ball is acting on the opposite side. When the ball is kept in air, gravity is the only force that acts on the ball. Hence in free fall, the object has no another forces except gravity.

Igoryamba3 years ago

5 0

D. Free fall

Explanation:

An object is said to be in free fall when there is only one force acting on the body, which is the force of gravity.

Near the Earth's surface, the force of gravity acting on a body is given by

F = mg

where

m is the mass of the body

g is the acceleration of gravity (its value is $9.8 m/s^2$ )

The direction of this force is downward (towards the Earth's centre).

If we apply Newton's second law on an object in free-fall, we can find its acceleration. In fact, we have:

$a=\frac{F}{m}$

And substituting F,

$a=\frac{mg}{m}=g=9.8 m/s^2$

So, every object in free-fall accelerates at $9.8 m/s^2$ towards the ground.

Learn more about free fall here:

brainly.com/question/1748290

brainly.com/question/11042118

brainly.com/question/2455974

brainly.com/question/2607086

#LearnwithBrainly

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3 years ago

A 0.547 kg pizza is thrown straight up in the air. At a height of 2.30 m above the surface of the earth it has a speed of 5.00 m

natima [27]

Answer:

The total mechanical energy of the pizza crust is 19.2 J.

Explanation:

Mechanical energy is that which a body or a system obtains as a result of the speed of its movement or its specific position, and which is capable of producing mechanical work. Then:

Potential energy + kinetic energy = total mechanical energy

Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.

Kinetic energy is defined as the amount of work necessary to accelerate a body of a certain mass and in a position of rest, until it reaches a certain speed.

Kinetic energy is represented by the following formula:

Ec = ½ *m*v²

Where Ec is kinetic energy, which is measured in Joules (J), m is mass measured in kilograms (kg), and v is velocity measured in meters over seconds (m / s).

In this case:

m=0.547 kg
v= 5 m/s

Replacing:

Ec = ½ *0.547 kg*(5 m/s)²

and solving you get:

Ec= 6.8375 J

On the other hand, potential energy is the energy that measures the ability of a system to perform work based on its position. In other words, this is the energy that a body has at a certain height above the ground.

Gravitational potential energy is the energy associated with the gravitational force. This will depend on the relative height of an object to some reference point, the mass, and the force of gravity. Then for an object with mass m, at height h, the expression applied to the gravitational energy of the object is:

Ep = m*g*h

Where Ep is the potential energy in joules (J), m is the mass in kilograms (kg) is h the height in meters (m) and g is the acceleration of fall in m / s² (approximately 9.81 m/s²)

In this case: