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Semmy [17]
3 years ago
7

Two ice skaters suddenly push off against one another starting from a stationary position. The 45-kg skater acquires a speed of

0.375 m/s relative to the ice. What speed does the 60-kg skater acquire relative to the ice?
Physics
1 answer:
timama [110]3 years ago
5 0

Answer:

Speed does the 60-kg skater acquire relative to the ice = 0.281 m/s

Explanation:

Momentum is conserved in this case.

Initial momentum = Final momentum.

Initial momentum = Initial momentum of skater 1 + Initial momentum of skater 2

Initial momentum = 45 x 0 + 60 x 0 = 0 kg m/s

Final momentum = 45 x 0.375 + 60 x u = 16.875 + 60 u

Here we need to find u.

We have

                  0 = 16.875 + 60 u

                   u = -0.281 m/s

Speed does the 60-kg skater acquire relative to the ice = 0.281 m/s

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Use the table below to answer the following questions. Substance Specific Heat (J/g•°C) water 4.179 aluminum 0.900 copper 0.385
lbvjy [14]

1. -8.78 \cdot 10^5 J

The energy lost by the water is given by:

Q=m C_s \Delta T

where

m = 3.0 kg = 3000 g is the mass of water

Cs = 4.179 J/g•°C is the specific heat

\Delta T=10.0C-80.0C=-70.0 C is the change in temperature

Substituting,

Q=(3000 g)(4.179 J/gC)(-70.0 C)=-8.78 \cdot 10^5 J

2. 3.24 \cdot 10^4 J

The energy added to the aluminium is given by:

Q=m C_s \Delta T

where

m = 0.30 kg = 300 g is the mass of aluminium

Cs = 0.900 J/g•°C is the specific heat

\Delta T=150.0 C-30.0C =120.0 C is the change in temperature

Substituting,

Q=(300 g)(0.900 J/gC)(120.0 C)=3.24 \cdot 10^4 J

3a. -5.6^{\circ}C

The temperature change of the water is given by

\Delta T=\frac{Q}{m C_s}

where

Q = -232 kJ=-2.32\cdot 10^5 J is the heat lost by the water

m=10.0 kg=10000 g is the mass of water

Cs = 4.179 J/g•°C is the specific heat

Substituting,

\Delta T=\frac{-2.32\cdot 10^5 J}{(10000g)(4.179 J/gC)}=5.6^{\circ}C

3b. +10.2^{\circ}C

The temperature change of the copper is given by

\Delta T=\frac{Q}{m C_s}

where

Q = 1.96 kJ=1960 is the heat added to the copper

m= 500 g is the mass of copper

Cs = 0.385 J/g•°C is the specific heat

Substituting,

\Delta T=\frac{1960 J}{(500g)(0.385 J/gC)}=10.2^{\circ}C

4. 42.9 g

The mass of the water sample is given by

m=\frac{Q}{C_S \Delta T}

where

Q=4300 J is the heat added

\Delta T=39 C-15 C=24C is the temperature change

Cs = 4.179 J/g•°C is the specific heat

Substituting,

m=\frac{4300 J}{(4.179 J/gC)(24 C)}=42.9 g

5. 115.5 J

The heat used to heat the copper is given by:

Q=m C_s \Delta T

where

m = 5.0 g is the mass of copper

Cs = 0.385 J/g•°C is the specific heat

\Delta T=80.0 C-20.0C =60.0 C is the change in temperature

Substituting,

Q=(5.0 g)(0.385 J/gC)(60.0 C)=115.5 J

6. 0.185 J/g•°C

The specific heat of iron is given by:

C_s = \frac{Q}{m \Delta T}

where

Q = -47 J is the heat released by the iron

m = 10.0 g is the mass of iron

\Delta T=25.0-50.4 C=-25.4 C is the change in temperature

Substituting,

C_s = \frac{-47 J}{(10.0 g)(-25.4 C)}=0.185 J/gC

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Answer:

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Explanation:

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Answer:

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<h3><u>Answer;</u></h3>

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