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3 years ago

The velocity vector of an object with a centripetal acceleration is never tangent to the circular path.

1 answer:

5 0

The velocity vector of an object with a centripetal acceleration is never tangent to the circular path is False.

Answer: False

Explanation:

Centripetal acceleration is a feature of objects in uniform circular motion. In that case velocity is along the tangent drawn to the circular path. For an object to be called accelerating its velocity should be variable but speed needn’t.

Even when the speed is constant an object can be accelerating. The direction of velocity of an object in uniform circular motion keeps changing continuously. This change in velocity in uniform circular motion is equal to the centripetal acceleration.

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Strontium−90 is one of the products of the fission of uranium−235. This strontium isotope is radioactive, with a half-life of 28

Ludmilka [50]

Answer : The time passed in years is 20.7 years.

Explanation :

Half-life = 28.1 years

First we have to calculate the rate constant, we use the formula :

$k=\frac{0.693}{t_{1/2}}$

$k=\frac{0.693}{28.1\text{ years}}$

$k=2.47\times 10^{-2}\text{ years}^{-1}$

Now we have to calculate the time passed.

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $2.47\times 10^{-2}\text{ years}^{-1}$

t = time passed by the sample = ?

a = initial amount of the reactant = 1.00 g

a - x = amount left after decay process = 0.600 g

Now put all the given values in above equation, we get

$t=\frac{2.303}{2.47\times 10^{-2}}\log\frac{1.00}{0.600}$

$t=20.7\text{ years}$

Therefore, the time passed in years is 20.7 years.

8 0

3 years ago

What is a characteristic of a gas?

DerKrebs [107]

Answer:

Gases have three characteristic properties: 1. they are easy to compress, 2. they expand to fill their containers, and 3.they occupy far more space than the liquids or solids from which they form. Compressibility. An internal combustion engine provides a good example of the ease with which gases can be compressed.

Explanation:

3 0

2 years ago

Read 2 more answers

Why do ice cubes always float at the top of a glass of water?

AnnZ [28]

Because water is a very very very very very unusual substance ... It's
the only known substance whose solid form is less dense than its liquid
form near the same temperature.

In other words, water is the only known substance for which a solid lump
of it floats in a liquid glass of it.

If that were not true ... if the behavior of the density of water around its
freezing temperature were the same as the density of all other known
substances ... then life on Earth would be impossible.

Think about that for a while ! Ya gotta admire whoever it was that designed water !

5 0

2 years ago

Read 2 more answers

A baseball is thrown through the air. It's initial velocity, described as a vector, is → v ( t = 0 ) = 17.1 ˆ i + 14.7 ˆ j m / s

ludmilkaskok [199]

Answer:

a = - 9.8 j ^ m/s²

Explanation:

This is a projectile launch problem, they give us the initial velocity in the two components

v₀ₓ = 17.1 m / s

$v_{oy}$ = 14.7 m / s

They indicate that the only acceleration that exists is the acceleration of gravity, which acts in the direction towards the center of the Earth, in general in a coordinate system it coincides with the direction of the y axis.

a = - g j ^

a = - 9.8 j ^ m /s²

6 0

3 years ago

A coffee filter of mass 1.2 grams dropped from a height of 1 m reaches the ground with a speed of 0.8 m/s. How much kinetic ener

iren [92.7K]

Answer: The energy gained by the air molecules is 0.011 J.

Explanation:

Law of conservation of energy states that energy can neither be created nor be destroyed but it can only be transformed from one form to another form.

Here, the potential energy of the coffee filter is getting converted into kinetic energy of the coffee filter and some energy is lost by it which is gained by the air molecules in the form of kinetic energy.

So, calculating the potential energy of coffee filter, we use the equation:

P = mgh

where,

m = mass of coffee filter = 1.2 g = $1.2\times 10^{-3}kg$ (Conversion used: 1 kg = 1000 g)