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2 years ago

Calculate how many half-lives are required for a number of radio-active nuclei to decrease to one-millionth of

Physics

2 answers:

Alex73 [517]2 years ago

6 0

Answer:

it would depend on which element u would be considering

Explanation:

as helium , oxygen , carbon ,sodium and other would be easier while plutonium , americium and other very radioactive elements would be harder

Naya [18.7K]2 years ago

4 0

Answer:

~ 20 half lives

Explanation:

(1/2) ^n = 1/1,000,000 n = number of half-lives

LOG both sides to get

n LOG 1/2 = -6

n = -6/(LOG (1/2)) = 19.931 or approx 20 half lives

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Question 7

erastova [34]

gdj dhbdh sbctcrxrxvh7sdchhcsh

4 0

3 years ago

1. What is the kinetic energy of a 1.75 kg ball travelling at a speed of 54 m/s?

Over [174]

Answer:

We conclude that the kinetic energy of a 1.75 kg ball traveling at a speed of 54 m/s is 2551.5 J.

Explanation:

Given

Mass m = 1.75 kg

Velocity v = 54 m/s

To determine

Kinetic Energy (K.E) = ?

We know that a body can possess energy due to its movement — Kinetic Energy.

Kinetic Energy (K.E) can be determined using the formula

$K.E=\frac{1}{2}mv^2$

where

m is the mass (kg)

v is the velocity (m/s)

K.E is the Kinetic Energy (J)

now substituting m = 1.75, and v = 54 in the formula

$K.E=\frac{1}{2}mv^2$

$K.E=\frac{1}{2}\left(1.75\right)\left(54\right)^2$

$K.E=1458\times 1.75$

$K.E=2551.5$ J

Therefore, the kinetic energy of a 1.75 kg ball traveling at a speed of 54 m/s is 2551.5 J.

7 0

3 years ago

From the top of a cliff, a person uses a slingshot to fire a pebble straight downward, which is the negative direction. The init

Talja [164]

Answer:

$\vec{a} = -(9.8~{\rm m/s^2})\^y$

Explanation:

Regardless of the initial velocity of the pebble, the acceleration of the pebble is equal to the gravitational acceleration which is equal to 9.8 m/s2 towards downwards direction.

This can be shown by Newton's Second Law. According to the law, the net force applied on an object is equal to mass times acceleration of that object.

During the downward motion, the only force acting on the pebble is the gravitational force, hence its acceleration is equal to gravitational acceleration.

8 0

3 years ago

A hockey player uses a hockey stick to hit a puck such that the stick provides an applied force on the puck The puck travels for

Norma-Jean [14]

Answer:

Explanation:

Let's analyze the situation presented in order to know which answer is correct.

When the stick collides with the puck, it exerts a force for a certain time and discants. / After this time the horizontal force decreases to zero and the disk continues to move by the action of the initial velocity on the x axis and the acceleration of gravity on the y axis.

Therefore, after the collision, the only force that acts on the disk is the gravitational attractive force (WEIGHT), directed on the axis and in a negative direction.

The correct answer is:

C) Since there is no frictional force exerted on the puck, a normal force is not exerted on the puck, but the gravitational force is exerted on the puck

4 0

3 years ago

The mass of a rocket decreases as it burns through its fuel. If the rocket engine produces constant force (thrust), how does the

Serjik [45]

Answer:

it increases-

Explanation:

When the mass of a rocket decreases as it burns through its fuel and the force ( thrust) is constant then by newtons second law of motion

F= ma here F is constant this means that ma= constant

⇒ m= F /a this implies that mass is inversely proportional to acceleration.

its means when the mass decreases the acceleration must increase. hence the acceleration increases

6 0

3 years ago