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3 years ago

How to calculate energy needed for a change of state

2 answers:

8 0

Change in temperature = (100 - 25) = 75.0°C.
change in thermal energy = mass × specific heat capacity × change in temperature.
= 0.200 × 4,180 × 75.0.
= 62,700 J (62.7kJ)

Alenkasestr [34]3 years ago

7 0

Answer:

change in temperature = (100 - 25) = 75.0°C.

change in thermal energy = mass × specific heat capacity × change in temperature.

= 0.200 × 4,180 × 75.0.

= 62,700 J (62.7kJ)

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A 0.250 kgkg toy is undergoing SHM on the end of a horizontal spring with force constant 300 N/mN/m. When the toy is 0.0120 mm f

konstantin123 [22]

Answer:

(a) The total energy of the object at any point in its motion is 0.0416 J

(b) The amplitude of the motion is 0.0167 m

Explanation:

Given;

mass of the toy, m = 0.25 kg

force constant of the spring, k = 300 N/m

displacement of the toy, x = 0.012 m

speed of the toy, v = 0.4 m/s

(a) The total energy of the object at any point in its motion

E = ¹/₂mv² + ¹/₂kx²

E = ¹/₂ (0.25)(0.4)² + ¹/₂ (300)(0.012)²

E = 0.0416 J

(b) the amplitude of the motion

E = ¹/₂KA²

$A = \sqrt{\frac{2E}{K} } \\\\A = \sqrt{\frac{2*0.0416}{300} } \\\\A = 0.0167 \ m$

$E = \frac{1}{2} mv_{max}^2\\\\v_{max} = \sqrt{\frac{2E}{m} } \\\\v_{max} = \sqrt{\frac{2*0.0416}{0.25} } \\\\v_{max} = 0.577 \ m/s$

8 0

3 years ago

Calculate the speed of the ball, vo in m/s, just after the launch. A bowling ball of mass m = 1.5 kg is launched from a spring c

klemol [59]

Answer:

$v_0=17.3m/s$

Explanation:

In this problem we have three important moments; the instant in which the ball is released (1), the instant in which the ball starts to fly freely (2) and the instant in which has its maximum height (3). From the conservation of mechanical energy, the total energy in each moment has to be the same. In (1), it is only elastic potential energy; in (2) and (3) are both gravitational potential energy and kinetic energy. Writing this and substituting by known values, we obtain:

$E_1=E_2=E_3\\\\U_e_1=U_g_2+K_2=U_g_3+K_3\\\\\frac{1}{2}kd^2=mg(d\sin\theta)+\frac{1}{2}mv_0^2=mgh+\frac{1}{2}m(v_0\cos\theta)^2$

Since we only care about the velocity $v_0$ , we can keep only the second and third parts of the equation and solve:

$mgd\sin\theta+\frac{1}{2}mv_0^2=mgh+\frac{1}{2}mv_0^2\cos^2\theta\\\\\frac{1}{2}mv_0^2(1-\cos^2\theta)=mg(h-d\sin\theta)\\\\v_0=\sqrt{\frac{2g(h-d\sin\theta)}{1-\cos^2\theta}}\\\\v_0=\sqrt{\frac{2(9.8m/s^2)(4.4m-(0.21m)\sin32\°)}{1-\cos^232\°}}\\\\v_0=17.3m/s$

So, the speed of the ball just after the launch is 17.3m/s.

4 0

3 years ago

If an ideal monatomic gas undergoes an adiabatic expansion, in which the volume increases by a factor of 4.0, by what factor doe

julsineya [31]

Answer:

e) 0.099

Explanation:

For an adiabatic expansion:

$P_1 V_1^{\gamma} = P_2 V_2^{\gamma}$

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

$\gamma$ is the adiabatic index (which is $\frac{5}{3}$ for an ideal monoatomic gas

In this problem, we have

$V_2 = 4 V_1$ since the volume increases by a factor 4

We can re-write the equation to find by what factor the pressure changes:

$\frac{P_2}{P_1}=(\frac{V_1}{V_2})^{\gamma}=(\frac{V_1}{4V_1})^{5/3}=(\frac{1}{4})^{5/3}=0.099$

8 0

3 years ago

An object moves with velocity v(t)=t^2-8t+7

solong [7]

a) write a polynomial expression for the position of the particle at any time t greater or equal to zero.
Position is found by integrating velocity:

s(t) = (t^3)/3 - 4t^2 + 7t + c
where c is a constant corresponding to the position at t=0. 

b) at what time(s) is the particle changing direction
the particle changes direction whenever the velocity is zero; the velocity function equals

(t-1)(t-7) a difference of squares so the zeros are 1 and 7, it changes direction at 1 second and 7 seconds. 

c) find the total distance traveled by the particle from t=0 and t=4
s(0) = c
s(1) = 8/3 + c
s(4) = 64/3 - 64 + 28 + c.

from 0 to 1 the particle travels 8/3 units. From 1 to 4 it travels -(64/3 - 36 - 8/3) = (-(56/3 - 108/3))
=-(-52/3) = 52/3 units

so in total it travels 52/3 + 8/3 =20 units

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3 years ago

Equal masses of water at 80°C and paraffin at 20°C are mixed in a container. The specific

erastovalidia [21]

30c that’s right my man Yk the drill

5 0

3 years ago

How to calculate energy needed for a change of state ​

How to calculate energy needed for a change of state