A tight knot can be easily opened by using a long spanner. Give reason.

Which of the following is considered to be a vector?               a.  temperature    b.  velocity    c.  time    d.  mass

Aferris wheel is a vertical, circular amusement ride with radius 9 m. riders sit on seats that swivel to remain horizontal. the ferris wheel rotates at a constant rate, going around once in 9 s. consider a rider whose mass is 56 kg. at the bottom of the ride, what is the perpendicular component of the rate of change of the rider's momentum? at the bottom of the ride, what is the vector force exerted by the seat on the rider?

Positrons are spontaneously emitted from the nuclei of