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3 years ago

How does a change in thermal energy cause matter to change from one state to another?

1 answer:

4 0

Thermal energy gives the particles of the substance kinetic energy because temperature is an average measure of kinetic enegy of the particle. If we give them thermal energy the particle will move faster, gaining enough energy to escape and become free. For example, from solid to liquid, the particles would espace their fixed position and be free to move as a liquid.

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The frequency of a person's pendulum is 0.3204 Hz when at a location where g is known to be exactly 9.800 m/s^2.

wel

Answer:

A) g = 9.751 m/s², B) h = 2.573 10⁴ m

Explanation:

The angular velocity of a pendulum is

w = √ g / L

Angular velocity and frequency are related.

w = 2π f

f = 1 / 2π √ g / L

A) with the initial data we can look for the pendulum length

L = 1 /4π² g / f²

L = 1 /4π² 9,800 / 0.3204²

L = 2.4181 m

The length of the pendulum does not change, let's look for the value of g for the new location

g = 4π² f² L

g = 4π² 0.3196² 2.4181

g = 9.75096 m / s²

g = 9.751 m/s²

B) The value of the acceleration of gravity can be found with the law of universal gravitation

F = G m M / $R_{e}$ ²

And Newton's second law

W = m g

W = F

G m M / $R_{e}$ ² = mg

g = G M / $R_{e}$ ²

$R_{e}$ ² = G M / g

Let's calculate

$R_{e}$ ² = 6.67 10⁻¹¹ 5.98 10²⁴ /9.75096

R = √ 4.0905 10¹³ = √ 40.9053 10¹²

R = 6.395726 10⁶ m

The height above sea level is

h = R - [tex]R_{e}[/tex

h = (6.395726 -6.37) 10⁶

h = 0.0257256 106

h = 2.573 10⁴ m

7 0

3 years ago

A child whose weight is 287 N slides down a 7.20 m playground slide that makes an angle of 31.0Â° with the horizontal. The coeff

natulia [17]

Answer:

$H =212.6 \ J$

$v = 7.647 \ m/s$

Explanation:

From the question we are told that

The child's weight is $W_c = 287 \ N$

The length of the sliding surface of the playground is $L = 7.20 \ m$

The coefficient of friction is $\mu = 0.120$

The angle is $\theta = 31.0 ^o$

The initial speed is $u = 0.559 \ m/s$

Generally the normal force acting on the child is mathematically represented as

=> $N = mg * cos \theta$

Note $m * g = W_c$

Generally the frictional force between the slide and the child is

$F_f = \mu * mg * cos \theta$

Generally the resultant force acting on the child due to her weight and the frictional force is mathematically represented as

$F =m* g sin(\theta) - F_f$

Here F is the resultant force and it is represented as $F = ma$

=> $ma = m* g sin(31.0) - \mu * mg * cos (31.0)$

=> $a = g sin(31.0)- \mu * g * cos (31.0)$

=> $a = 9.8 * sin(31.0) - 0.120 * 9.8 * cos (31.0)$

=> $a = 4.039 \ m/s^2$

$F_f = 0.120 * 287 * cos (31.0)$

=> $F_f = 29.52 \ N$

Generally the heat energy generated by the frictional force which equivalent tot the workdone by the frictional force is mathematically represented as

$H = F_f * L$