Physics Answers

if the period of rotation is 3 seconds what is its angular frequency

A scientist working late at night in her low-temperature physics laboratory decides to have a cup of hot tea, but discovers the lab hot plate is broken. Not to be deterred, she puts about 8.00 oz of water, at 12.0°C, from the tap into a lab dewar (essentially a large thermos bottle) and begins shaking it up and down. With each shake the water is thrown up and falls back down a distance of 25.6 cm.

Is this practically possible?

A scientist working late at night in her low-temperature physics laboratory decides to have a cup of hot tea, but discovers the lab hot plate is broken. Not to be deterred, she puts about 8.00 oz of water, at 12.0°C, from the tap into a lab dewar (essentially a large thermos bottle) and begins shaking it up and down. With each shake the water is thrown up and falls back down a distance of 25.6 cm.

 If she can complete 30 shakes per minute, how long will it take for the water to reach 79.8°C?

A 7.70-kg steel ball at 18.7°C is dropped from a height of 12.7 m into an insulated container with 4.50 L of water at 10.1°C. If no water splashes, what is the final temperature of the water and steel? The specific heat of steel and water is 450 J/(kg·K) and 4186 J/(kg·K) respectively.

A 15 A current flows in a device that has a resistance of

0.15Ω. Compute the rate of heat production by the device.

The heating element in a hair dryer is rated at 5kW and

220V . How much current does it draw?

An electric toaster has a resistance of 12 Ω. What current will it draw

from a 120 V supply?

What is the potential difference across a hand-held fan that has a

resistance of 120 Ω and a current of 50 mA flowing through it?

What is the resistance in a circuit if a potential difference of 110 V

causes a current of 10 A?

Calculate the current an electric clothes dryer draws when it is

connected to a 230 V source and has a resistance of 9.2 Ω