1.in an x-ray tube,electrons striking a target are brought to rest,causing x-rays to be emitted.in a particular x-ray tube,the maximum frequency of the emitted continuum x-ray spectrum is F0,if the voltage across the tube is doubled,the maximum frequency is?
2.an object of mass M hands from a string that is fixed to the ceiling of a car.At the instant shown above,the car is moving into the plane of the page at constant speed V as it turns to the left around a horizontal curve of radius R.what is the correct expression for the angle G of the string with repsect to the vertical?
圖就是一個(gè)小球M被一根右傾的繩子吊住,繩子和鉛垂線成G角.