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1 year ago

Which of the following substances will show the smallest change in temperature when equal amounts of energy are absorbed?

2 answers:

3 0

It would be water because if you freeze it than you will still be able to see it and if you boil it than you will be able to see it disappear.

IgorLugansk [536]1 year ago

3 0

The correct answer of this question is : Water

EXPLANATION :

Before going to answer this question, first we have to understand the specific heat capacity.

The amount of heat required to raise the temperature of one gram of substance through one degree celsius is known as the specific heat capacity.

Hence, more is the specific heat of the substance, more is the heat required to change its temperature.

As per the questions, same amount of heat is given to water,air, sand and concrete.

The specific heat of water is more as compared to sand and concrete.

The specific heat of air is of two types like specific heat at constant pressure and specific heat at constant volume. Both these values are temperature dependent. Normally, specific heat at constant volume is less than water.

Hence, water will show the smallest change in temperature.

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If you used 1000 J of energy to throw a ball, would it travel faster if you threw the ball (ignoring air resistance)

wolverine [178]

To solve this problem it is necessary to apply the kinematic equations of Energy for which the rotation of a circular body is described as

$KE = \frac{1}{2}mv^2+\frac{1}{2}I\omega^2$

Where,

m = Mass of the Vall

v = Velocity

I = Moment of inertia abouts its centre of mass

$\omega =$ Angular speed

Basically the two sums of energies is the consideration of translational and rotational kinetic energy.

a. so that it was also rotating?

The ball is rotating means that it has some angular speed:

$KE = \frac{1}{2}mv^2+\frac{1}{2}I\omega^2$

$1000J = \frac{1}{2}mv^2+\frac{1}{2}I\omega^2$

When there is a little angular energy (and not linear energy to travel faster), translational energy will be greater than the 1000J applied.

$1000J > \frac{1}{2}mv^2$

The ball will not go faster.

c. so that it wasn't rotating?

For the case where the angular velocity does not rotate it is zero therefore

$KE = \frac{1}{2}mv^2+\frac{1}{2}I\omega^2$

$1000J = \frac{1}{2}mv^2+\frac{1}{2}I(0)^2$

$1000J = \frac{1}{2}mv^2$

All energy is transoformed into translational energy so it is possible to go faster. This option is CORRECT.

b. It makes no difference.

Although the order presented is different, I left this last option because as we can see with the previous two parts if there is an affectation regarding angular movement, therefore it is not correct.

6 0

1 year ago

You decide to work at a heart rate of 150 instead of 120. What area of F.I.T.T. did you change?

Rina8888 [55]

Key concepts

Heart rate

Exercising

The heart

Cardiovascular system

Health

Introduction

As Valentine's Day approaches, we're increasingly confronted with "artistic" images of the heart. Real hearts hardly resemble to two-lobed shapes adorning cards and candy boxes this time of year. And the actual shape of the human heart is important for its function of supplying blood to the entire body. You have likely noticed that your heart beats more quickly when you exercise. But have you ever taken the time to observe how long it takes to return to its normal rate after you're done exercising? In this science activity you'll get to do some exercises to explore your own heart-rate recovery time.

Background

Your heart is continuously beating to keep blood circulating throughout your body. Its rate changes depending on your activity level; it is lower while you are asleep and at rest and higher while you exercise—to supply your muscles with enough freshly oxygenated blood to keep the functioning at a high level. Because your heart is also a muscle, exercise, in turn, helps keep it healthy. The American Heart Association recommends that a person does exercise that is vigorous enough to raise their heart rate to their target heart-rate zone—50 percent to 85 percent of their maximum heart rate, which is 220 beats per minute (bpm) minus their age for adults—for at least 30 minutes on most days, or about 150 minutes a week in total. So for a 20-year-old, the maximum heart rate would be 200 bpm, with a target heart-rate zone of 100 to 170 bpm. (For those 19 or younger, target zones can vary more than they do for adults.)

i think it will help you...if it help you ...please mark brainless

8 0

2 years ago

A fisherman is fishing from a bridge and is using a "50.0-N test line." In other words, the line will sustain a maximum force of

umka21 [38]

Answer:(a) 50 N

(b)38.34 N

Explanation:

Given

Maximum tension(T) in line 50 N

(a)If line is moving up with constant velocity i.e. there is no acceleration

This will happen when Tension is equal to weight of Fish