A teacher stands well back from an outside doorway 0.88 m wide, and blows a whistle of frequency 780 Hz. Ignoring reflections, estimate at what angle (s) it is not possible to hear the whistle clearly on the playground outside the doorway.

How can you make a magnet that turns on and off

When a rattlesnake strikes, its head accelerates from rest to a speed of 28 m/s in 0.65 seconds. Assume for simplicity that the only moving part of the snake is its head of mass 170 g.

Is light made of elements and atoms

A spring with a spring constant of 2500 n/m. is stretched 4.00 cm. what is the work required to stretch the spring?

A proton is confined within an atomic nucleus of diameter 3.60 fm. part a estimate the smallest range of speeds you might find for a proton in the nucleus.

Ari, a young patient who is regularly treated by a psychiatrist, feels compelled to carry out repetitive tasks the same way very frequently. If Ari does not conduct these tasks with extreme precision, he can feel extremely nervous and uncomfortable.

A friend says, "Stars produce energy by a fusion chain reaction of helium into hydrogen." Evaluate the validity of this statement. A) It is an valid statement. Stars produce energy by a fusion chain reaction of hydrogen into helium.

If the mass of a material is 42 grams and the volume of the material is 15 cm^3, what would the density of the material be? answer: Unit:

35. An object of mass m moving at speed v0 strikes an object of mass 2m which had been at rest. The first object bounces backward along its initial path at speed v0.

Calculate the change in the canister pressure when the outside temperature changes from 72 ∘f to 80 ∘ f.