Quan sát sóng dừng trên sợi dây dài 60cm cố định hai đầu, thấy có 3 nút (bao gồm cả hai nút hai đầu) và 2 bụng. Bước sóng của sóng lan truyền trên sợi dây là:
A. 30cm. B. 40cm. C. 20cm. D. 60cm.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.

Which transition by an electron will release the greatest amount of energy? oa ob oc od

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?