Astronaut John's mass is 75 kg. He is floating at rest in the space station holding a 5.0 kg pillow. When his friend Bill enters the room, John throws the pillow at Bill with a velocity of 25 m/s. Immediately after letting go of the pillow, what is John's velocity? A.
1.7 m/s towards Bill
B.
1.7 m/s away from Bill
C.
15 m/s towards Bill
D.
15 m/s away from Bill

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.

State the right hand rule of the direction of magnetic field in a conductor carrying current

Amachinist turns the power on to a grinding wheel, at rest, at time t = 0 s. the wheel accelerates uniformly for 10 s and reaches the operating angular velocity of 96 rad/s. the wheel is run at that angular velocity for 40 s and then power is shut off. the wheel slows down uniformly at 1.5 rad/s2 until the wheel stops. in this situation, the time interval of deceleration is closest to: