According to Newton’s second law, the force required to accelerate an object is equal to
A) its acceleration divided by its mass.
B) its mass times the acceleration.
C) its mass divided by the velocity.
D) its weight times the velocity.
The radius of Earth is about __________ mi.
A) 6000
B) 8000
C) 4000
D) 2000
For a longitudinal mechanical wave, the particle motion is
A) parallel to the direction of the wave velocity.
B) perpendicular to the direction of the wave velocity.
C) both parallel and perpendicular to the direction of the wave velocity.
D) in all directions.