: Ném một vật lên cao với vận tốc ban đầu v0 = 15(m/s) theo phương hợp với phương ngang một góc =30. Bỏ qua sức cản khơng khí lấy g = 9,8(m/s2). Bán kính cong của quỹ đạo tại vị trí cao nhất của vật là:

Wo audio speakers are placed on a vertical rail. speaker a is placed at head-level while speaker b is place at some variable height, \delta yδy, above speaker a. both speakers receive simultaneous input from a sine-wave generator so the speakers each produce a pure sinusoidal sound wave with a wavelength of 0.531 meters. calculate the lowest height that speaker b can be placed above speaker a to produce a minimum of sound heard by person standing \delta x = 7.86δx=7.86 meters directly in front of speaker a.

Akg a of 55 m at an of 11 ? . if is at 98 km/h,be ?

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.