A tree leaf of mass of 0.80 g and specific heat of $3700 \mathrm{J} / \mathrm{kg} \cdot^{\circ} \mathrm{C}$ absorbs energy from the sunlight at a rate of $2.8 \mathrm{J} / \mathrm{s}$.If this energy is not removed from the leaf,how much does the temperature of the leaf change in 1 min?

A well-insulated valve is used to throttle steam from $8 \mathrm{~MPa}$ and $500^{\circ} \mathrm{C}$ to $6 \mathrm{~MPa}$. Determine the final temperature of the steam.

What is the amount of heat input to your skin when it receives the heat released

by 25.0 g of steam initially at $100.0^{\circ} C$, when it is cooled to skin temperature ($34.0^{\circ} \mathrm{C}$)?

A well-insulated valve is used to throttle steam from 8 MPa and $350^\circ C$ to 2 MPa. Determine the final temperature of the steam.

Your friend says that natural convection would not work on a spaceship orbiting the Earth. Do you agree or disagree with her statement? Explain.

A $500-g$ aluminum container holds $300 \mathrm{g}$ of water. The water and aluminum are initially at $40^{\circ} \mathrm{C}$. A $200-\mathrm{g}$ iron block at $0^{\circ} \mathrm{C}$ is added to the water. What can you determine using this information? State any assumptions you used. List all physics ideas that you used to solve this problem.

You add $20^{\circ} \mathrm{C}$ water to $0.20 \mathrm{kg}$ of $40^{\circ} \mathrm{C}$ soup. After a little mixing, the water and soup mixture is at $34^{\circ} \mathrm{C}$. The specific heat of the soup is $3800 \mathrm{J} / \mathrm{kg} \cdot^{\circ} \mathrm{C}$.Determine everything you can using this information.

A $200\text{-g}$ aluminum calorimeter contains $500 \text{~g}$ of water at $20.0^{\circ} \text{C}$. An aluminum shot with a mass equal to $300 \text{~g}$ is heated to $100.0^{\circ} \text{C}$ and is then placed in the calorimeter. Find the final temperature of the system, assuming that there is no heat transfer to the surroundings.

A 200-g block of copper at a temperature of 90$^ { \circ } \mathrm { C }$ is dropped into 400 g of water at 27$^ { \circ } \mathrm { C }$. The water is contained in a 300-g glass container. What is the final temperature of the mixture?

Which legislation imposes a tax on the chemical and petroleum industries to generate funds to pay for the cleanup of hazardous substances? (a) RCRA, (b) Cradle-to-Grave Act, (c) The National Priorities List, (d) HSWA, (e) CERCLA.

Find the smallest integer $k \geq 0$ such that adding k to each entry of the given matrix produces a matrix with all positive payoffs.

$$\left[\begin{array}{ll}{0} & {1} \\ {2} & {0}\end{array}\right]$$

Estimate the time interval required for a $600-\mathrm{kg}$ cast iron car engine to warm from $30^{\circ} \mathrm{C}$ to $1500^{\circ} \mathrm{C}$ (approximately the melting temperature of iron) if burning fuel in the engine as it idles produces thermal energy at a rate of $8000 \mathrm{J} / \mathrm{s}$ and none of the energy escapes the car engine.

Simplify the expression.

$$\log 10 ^ { 3 }$$

Two resistances,

$$R _ { 1 } \text { and } R _ { 2 }$$

are connected in series across a 12-V battery. The current increases by 0.20 A when

$$R _ { 2 }$$

is removed, leaving

$$R _ { 1 }$$

connected across the battery. However, the current increases by just 0.10 A when

$$R _ { 1 }$$

is removed , leaving

$$R _ { 2 }$$

connected across the battery. Find

$$R_2$$